fix(budget): correct VAT storage semantics for planned amounts

client/src/components/budget/BudgetLineCard.tsx

@@ -1,7 +1,7 @@
 import { type ReactNode } from 'react';
 import { useTranslation } from 'react-i18next';
 import type { BaseBudgetLine, ConfidenceLevel } from '@cornerstone/shared';
-import { CONFIDENCE_MARGINS } from '../../lib/budgetConstants.js';
+import { CONFIDENCE_MARGINS, effectivePlannedAmount } from '../../lib/budgetConstants.js';
 import { useFormatters } from '../../lib/formatters.js';
 import { getCategoryDisplayName } from '../../lib/categoryUtils.js';
 import styles from './BudgetLineCard.module.css';
@@ -54,12 +54,12 @@ export function BudgetLineCard({
                 {isQuotation ? t('vendorDetail.quotedAmount') : 'Invoiced Amount'}
               </span>
               <span className={styles.plannedSecondary}>
-                (planned: {formatCurrency(line.plannedAmount)})
+                (planned: {formatCurrency(effectivePlannedAmount(line))})
               </span>
             </>
           ) : (
             <>
-              <span className={styles.amount}>{formatCurrency(line.plannedAmount)}</span>
+              <span className={styles.amount}>{formatCurrency(effectivePlannedAmount(line))}</span>
               <span className={styles.confidence}>
                 {confidenceLabels[line.confidence]}
                 {CONFIDENCE_MARGINS[line.confidence] > 0 && (

client/src/components/budget/BudgetSection.tsx

@@ -7,7 +7,7 @@ import type {
   SubsidyProgram,
 } from '@cornerstone/shared';
 import type { UseBudgetSectionReturn } from '../../hooks/useBudgetSection.js';
-import { CONFIDENCE_LABELS } from '../../lib/budgetConstants.js';
+import { CONFIDENCE_LABELS, effectivePlannedAmount } from '../../lib/budgetConstants.js';
 import { BudgetLineCard } from './BudgetLineCard.js';
 import { BudgetLineForm } from './BudgetLineForm.js';
 import { SubsidyLinkSection } from './SubsidyLinkSection.js';
@@ -133,7 +133,7 @@ export function BudgetSection<T extends BaseBudgetLine>({
             (sum, line) => sum + (line.invoiceLink?.itemizedAmount || 0),
             0,
           );
-          const plannedTotal = groupLines.reduce((sum, line) => sum + line.plannedAmount, 0);
+          const plannedTotal = groupLines.reduce((sum, line) => sum + effectivePlannedAmount(line), 0);
 
           return (
             <InvoiceGroup

client/src/hooks/useBudgetSection.ts

@@ -207,9 +207,7 @@ export function useBudgetSection<T extends BaseBudgetLine>(
         return;
       }
 
-      // Calculate planned amount: qty * price * (includesVat ? 1 : 1.19)
-      const multiplier = budgetForm.includesVat ? 1 : 1.19;
-      plannedAmount = Math.round(qty * price * multiplier * 100) / 100;
+      plannedAmount = Math.round(qty * price * 100) / 100;
     }
 
     setIsSavingBudget(true);

client/src/lib/budgetConstants.ts

@@ -1,8 +1,8 @@
 import type { ConfidenceLevel, BaseBudgetLine } from '@cornerstone/shared';
-import { CONFIDENCE_MARGINS } from '@cornerstone/shared';
+import { CONFIDENCE_MARGINS, effectivePlannedAmount } from '@cornerstone/shared';
 
-// Re-export CONFIDENCE_MARGINS for convenience in client code
-export { CONFIDENCE_MARGINS };
+// Re-export for convenience in client code
+export { CONFIDENCE_MARGINS, effectivePlannedAmount };
 
 /**
  * Human-readable labels for confidence levels used in budget forms and displays.
@@ -36,7 +36,7 @@ export interface BudgetTotals {
  * @returns BudgetTotals object with planned, actual, and range values
  */
 export function computeBudgetTotals(budgetLines: BaseBudgetLine[]): BudgetTotals {
-  const totalPlanned = budgetLines.reduce((sum, b) => sum + b.plannedAmount, 0);
+  const totalPlanned = budgetLines.reduce((sum, b) => sum + effectivePlannedAmount(b), 0);
   const totalActualCost = budgetLines.reduce((sum, b) => sum + b.actualCost, 0);
 
   const totalMinPlanned = budgetLines.reduce((sum, b) => {
@@ -45,7 +45,7 @@ export function computeBudgetTotals(budgetLines: BaseBudgetLine[]): BudgetTotals
       return sum + b.actualCost;
     }
     const margin = CONFIDENCE_MARGINS[b.confidence] ?? 0;
-    return sum + b.plannedAmount * (1 - margin);
+    return sum + effectivePlannedAmount(b) * (1 - margin);
   }, 0);
 
   const totalMaxPlanned = budgetLines.reduce((sum, b) => {
@@ -54,7 +54,7 @@ export function computeBudgetTotals(budgetLines: BaseBudgetLine[]): BudgetTotals
       return sum + b.actualCost;
     }
     const margin = CONFIDENCE_MARGINS[b.confidence] ?? 0;
-    return sum + b.plannedAmount * (1 + margin);
+    return sum + effectivePlannedAmount(b) * (1 + margin);
   }, 0);
 
   const hasPlannedRange = Math.abs(totalMaxPlanned - totalMinPlanned) > 0.01;

client/src/pages/HouseholdItemDetailPage/HouseholdItemDetailPage.tsx

@@ -211,21 +211,18 @@ export function HouseholdItemDetailPage() {
       quantity: line.quantity !== null ? String(line.quantity) : '',
       unit: line.unit ?? '',
       unitPrice: line.unitPrice !== null ? String(line.unitPrice) : '',
-      includesVat: line.quantity !== null ? (line.includesVat ?? true) : false,
+      includesVat: line.includesVat ?? true,
     }),
     toPayload: (form: BudgetLineFormState) => ({
       description: form.description.trim() || null,
-      plannedAmount:
-        form.pricingMode === 'direct' && form.includesVat
-          ? Math.round((parseFloat(form.plannedAmount) / 1.19) * 100) / 100
-          : parseFloat(form.plannedAmount),
+      plannedAmount: parseFloat(form.plannedAmount),
       confidence: form.confidence,
       budgetSourceId: form.budgetSourceId,
       vendorId: form.vendorId || null,
       quantity: form.pricingMode === 'unit' && form.quantity ? parseFloat(form.quantity) : null,
       unit: form.pricingMode === 'unit' && form.unit ? form.unit : null,
       unitPrice: form.pricingMode === 'unit' && form.unitPrice ? parseFloat(form.unitPrice) : null,
-      includesVat: form.pricingMode === 'unit' ? form.includesVat : null,
+      includesVat: form.includesVat,
     }),
     entityId: id ?? '',
     defaultBudgetSourceId: budgetSources.find((s) => s.isDiscretionary)?.id,

client/src/pages/WorkItemDetailPage/WorkItemDetailPage.tsx

@@ -264,22 +264,19 @@ export default function WorkItemDetailPage() {
       quantity: line.quantity !== null ? String(line.quantity) : '',
       unit: line.unit ?? '',
       unitPrice: line.unitPrice !== null ? String(line.unitPrice) : '',
-      includesVat: line.quantity !== null ? (line.includesVat ?? true) : false,
+      includesVat: line.includesVat ?? true,
     }),
     toPayload: (form: BudgetLineFormState): CreateWorkItemBudgetRequest => ({
       description: form.description.trim() || null,
-      plannedAmount:
-        form.pricingMode === 'direct' && form.includesVat
-          ? Math.round((parseFloat(form.plannedAmount) / 1.19) * 100) / 100
-          : parseFloat(form.plannedAmount),
+      plannedAmount: parseFloat(form.plannedAmount),
       confidence: form.confidence,
       budgetCategoryId: form.budgetCategoryId || null,
       budgetSourceId: form.budgetSourceId,
       vendorId: form.vendorId || null,
       quantity: form.pricingMode === 'unit' && form.quantity ? parseFloat(form.quantity) : null,
       unit: form.pricingMode === 'unit' && form.unit ? form.unit : null,
       unitPrice: form.pricingMode === 'unit' && form.unitPrice ? parseFloat(form.unitPrice) : null,
-      includesVat: form.pricingMode === 'unit' ? form.includesVat : null,
+      includesVat: form.includesVat,
     }),
     entityId: id ?? '',
     defaultBudgetSourceId: budgetSources.find((s) => s.isDiscretionary)?.id,

server/src/db/migrations/0031_fix_vat_storage_semantics.sql

@@ -0,0 +1,9 @@
+-- Convert existing unit-pricing budget lines (includes_vat = false) from
+-- VAT-inclusive storage back to net amounts. Display now applies × 1.19.
+UPDATE work_item_budgets
+SET planned_amount = ROUND(planned_amount / 1.19, 2)
+WHERE quantity IS NOT NULL AND includes_vat = 0;
+
+UPDATE household_item_budgets
+SET planned_amount = ROUND(planned_amount / 1.19, 2)
+WHERE quantity IS NOT NULL AND includes_vat = 0;

server/src/services/budgetOverviewService.ts

@@ -51,21 +51,24 @@ export function getBudgetOverview(db: DbType): BudgetOverview {
     plannedAmount: number;
     confidence: string;
     budgetCategoryId: string | null;
+    includesVat: number | null;
   }>(
     sql`SELECT
       id              AS id,
       work_item_id    AS entityId,
       planned_amount  AS plannedAmount,
       confidence      AS confidence,
-      budget_category_id AS budgetCategoryId
+      budget_category_id AS budgetCategoryId,
+      includes_vat    AS includesVat
     FROM work_item_budgets
     UNION ALL
     SELECT
       id              AS id,
       household_item_id AS entityId,
       planned_amount  AS plannedAmount,
       confidence      AS confidence,
-      budget_category_id AS budgetCategoryId
+      budget_category_id AS budgetCategoryId,
+      includes_vat    AS includesVat
     FROM household_item_budgets`,
   );
 
@@ -197,10 +200,17 @@ export function getBudgetOverview(db: DbType): BudgetOverview {
   const fixedSubsidyLineCountCache = new Map<string, number>();
   let totalReductions = 0;
 
+  // VAT helper: convert stored net amount to effective amount if VAT not included
+  // SQLite returns 0/1 for boolean, so includesVat === 0 means false (VAT should be applied)
+  const effective = (l: { plannedAmount: number; includesVat: number | null }): number =>
+    l.includesVat === 0
+      ? Math.round(l.plannedAmount * 1.19 * 100) / 100
+      : l.plannedAmount;
+
   for (const line of budgetLines) {
     const margin = CONFIDENCE_MARGINS[line.confidence as keyof typeof CONFIDENCE_MARGINS] ?? 0;
-    const rawMin = line.plannedAmount * (1 - margin);
-    const rawMax = line.plannedAmount * (1 + margin);
+    const rawMin = effective(line) * (1 - margin);
+    const rawMax = effective(line) * (1 + margin);
 
     // Compute subsidy reduction for this line
     let subsidyReduction = 0;
@@ -218,10 +228,10 @@ export function getBudgetOverview(db: DbType): BudgetOverview {
             continue;
         }
 
-        // Determine cost basis: use invoice amount if available, otherwise planned amount
+        // Determine cost basis: use invoice amount if available, otherwise effective planned amount
         const costBasis = lineInvoiceMap.has(line.id)
           ? lineInvoiceMap.get(line.id)!.actualCost
-          : line.plannedAmount;
+          : effective(line);
 
         // This subsidy applies to this line
         if (meta.reductionType === 'percentage') {
@@ -330,6 +340,7 @@ export function getBudgetOverview(db: DbType): BudgetOverview {
       plannedAmount: number;
       confidence: string;
       budgetCategoryId: string | null;
+      includesVat: number | null;
     }[]
   >();
   for (const line of budgetLines) {
@@ -345,11 +356,11 @@ export function getBudgetOverview(db: DbType): BudgetOverview {
   for (const [entityId, linkedSubsidyIds] of entitySubsidyMap) {
     const entityLines = linesByEntity.get(entityId) ?? [];
 
-    // Build engine inputs from the entity's budget lines
+    // Build engine inputs from the entity's budget lines (using effective amounts)
     const engineLines = entityLines.map((line) => ({
       id: line.id,
       budgetCategoryId: line.budgetCategoryId,
-      plannedAmount: line.plannedAmount,
+      plannedAmount: effective(line),
       confidence: line.confidence,
     }));
 

shared/src/index.ts

@@ -170,6 +170,7 @@ export type {
   BudgetSummary,
   BudgetLineInvoiceLink,
 } from './types/budget.js';
+export { effectivePlannedAmount } from './types/budget.js';
 
 // Subsidy Programs
 export type {

shared/src/types/budget.ts

@@ -92,6 +92,20 @@ export interface BaseBudgetLine {
   updatedAt: string;
 }
 
+/**
+ * Returns the effective planned amount for display and aggregation.
+ * When includesVat is explicitly false, the stored amount is net; multiply by 1.19.
+ * null is treated as true (use as-is).
+ */
+export function effectivePlannedAmount(line: {
+  plannedAmount: number;
+  includesVat: boolean | null;
+}): number {
+  return line.includesVat === false
+    ? Math.round(line.plannedAmount * 1.19 * 100) / 100
+    : line.plannedAmount;
+}
+
 /**
  * Request body for creating a new budget line.
  * Used for both work item and household item budgets.