diff --git a/src/api/admin/admin.service.spec.ts b/src/api/admin/admin.service.spec.ts
index a03ab99..e0c5c33 100644
--- a/src/api/admin/admin.service.spec.ts
+++ b/src/api/admin/admin.service.spec.ts
@@ -449,8 +449,8 @@ describe('AdminService', () => {
         },
       ])
       .mockResolvedValueOnce([
-        { total_amount: '12.00' },
-        { total_amount: '27.50' },
+        { gross_amount: '12.00', total_amount: '15.96' },
+        { gross_amount: '27.50', total_amount: '36.58' },
       ]);
     topcoderChallengesService.getChallengeById.mockResolvedValue({
       billing: {
@@ -487,7 +487,10 @@ describe('AdminService', () => {
       },
     });
     expect(prisma.payment.findMany).toHaveBeenNthCalledWith(2, {
-      select: { total_amount: true },
+      select: {
+        gross_amount: true,
+        total_amount: true,
+      },
       where: {
         billing_account: '80001012',
         currency: 'USD',
@@ -584,8 +587,8 @@ describe('AdminService', () => {
         },
       ])
       .mockResolvedValueOnce([
-        { total_amount: '150.00' },
-        { total_amount: '25.00' },
+        { gross_amount: '150.00', total_amount: '199.50' },
+        { gross_amount: '25.00', total_amount: '33.25' },
       ]);
     topcoderChallengesService.getChallengeById.mockResolvedValue({
       billing: {
diff --git a/src/api/admin/admin.service.ts b/src/api/admin/admin.service.ts
index 7ab1791..348e0db 100644
--- a/src/api/admin/admin.service.ts
+++ b/src/api/admin/admin.service.ts
@@ -33,6 +33,7 @@ import {
   TopcoderChallengeInfo,
   TopcoderChallengesService,
 } from 'src/shared/topcoder/challenges.service';
+import { resolveChallengeMemberPaymentAmount } from 'src/shared/payments/challenge-payment-amount.util';
 import {
   PaymentCycle,
   WinningPaymentDetailsDto,
@@ -588,12 +589,14 @@ export class AdminService {
   }
 
   /**
-   * Sums non-cancelled USD payment rows for a challenge and billing account.
+   * Sums non-cancelled USD member-payment rows for a challenge and billing
+   * account.
    *
    * @param challengeId challenge external id stored on winnings.
    * @param billingAccountId billing account stored on payment rows.
-   * @returns total member-payment amount that should remain locked or consumed
-   * for the challenge billing-account line item.
+   * @returns Total member-payment amount that should remain locked or consumed
+   * for the challenge billing-account line item. `gross_amount` is used before
+   * `total_amount` so fee-inclusive totals are not marked up again.
    * @throws Prisma errors when the aggregate query fails.
    */
   private async getActiveChallengePaymentTotal(
@@ -601,7 +604,10 @@ export class AdminService {
     billingAccountId: number,
   ): Promise<number> {
     const payments = await this.prisma.payment.findMany({
-      select: { total_amount: true },
+      select: {
+        gross_amount: true,
+        total_amount: true,
+      },
       where: {
         billing_account: String(billingAccountId),
         currency: PrizeType.USD,
@@ -614,7 +620,12 @@ export class AdminService {
     });
     const totalAmount = payments.reduce(
       (sum, paymentRow) =>
-        sum.plus(new Prisma.Decimal(paymentRow.total_amount ?? 0)),
+        sum.plus(
+          resolveChallengeMemberPaymentAmount({
+            grossAmount: paymentRow.gross_amount,
+            totalAmount: paymentRow.total_amount,
+          }),
+        ),
       new Prisma.Decimal(0),
     );
 
diff --git a/src/api/winnings/winnings.service.spec.ts b/src/api/winnings/winnings.service.spec.ts
index 2c75172..d561500 100644
--- a/src/api/winnings/winnings.service.spec.ts
+++ b/src/api/winnings/winnings.service.spec.ts
@@ -519,8 +519,8 @@ describe('WinningsService', () => {
       status: 'COMPLETED',
     });
     tx.payment.findMany.mockResolvedValue([
-      { total_amount: '75.00' },
-      { total_amount: '25.00' },
+      { gross_amount: '75.00', total_amount: '99.75' },
+      { gross_amount: '25.00', total_amount: '33.25' },
     ]);
 
     await service.createWinningWithPayments(
@@ -546,7 +546,10 @@ describe('WinningsService', () => {
     );
 
     expect(tx.payment.findMany).toHaveBeenCalledWith({
-      select: { total_amount: true },
+      select: {
+        gross_amount: true,
+        total_amount: true,
+      },
       where: {
         billing_account: '80001012',
         currency: PrizeType.USD,
@@ -615,8 +618,8 @@ describe('WinningsService', () => {
       status: 'DRAFT',
     });
     tx.payment.findMany.mockResolvedValue([
-      { total_amount: '100.00' },
-      { total_amount: '50.25' },
+      { gross_amount: '100.00', total_amount: '120.00' },
+      { gross_amount: '50.25', total_amount: '60.30' },
     ]);
 
     await service.createWinningWithPayments(
@@ -645,7 +648,10 @@ describe('WinningsService', () => {
       'challenge-id',
     );
     expect(tx.payment.findMany).toHaveBeenCalledWith({
-      select: { total_amount: true },
+      select: {
+        gross_amount: true,
+        total_amount: true,
+      },
       where: {
         billing_account: '80001012',
         currency: PrizeType.USD,
diff --git a/src/api/winnings/winnings.service.ts b/src/api/winnings/winnings.service.ts
index a4ae53c..475abb1 100644
--- a/src/api/winnings/winnings.service.ts
+++ b/src/api/winnings/winnings.service.ts
@@ -40,6 +40,7 @@ import {
   TopcoderChallengesService,
 } from 'src/shared/topcoder/challenges.service';
 import { TopcoderM2MHttpError } from 'src/shared/topcoder/topcoder-m2m.service';
+import { resolveChallengeMemberPaymentAmount } from 'src/shared/payments/challenge-payment-amount.util';
 
 const BUDGET_LEDGER_DECIMAL_PLACES = 4;
 const PAYMENT_DECIMAL_PLACES = 2;
@@ -556,14 +557,14 @@ export class WinningsService {
   }
 
   /**
-   * Sums non-cancelled persisted USD payment rows for a challenge and billing
-   * account.
+   * Sums non-cancelled persisted USD member-payment rows for a challenge and
+   * billing account.
    *
    * @param tx active Prisma transaction.
    * @param challengeId challenge external id stored on winnings.
    * @param billingAccountId billing account stored on payment rows.
-   * @returns Payment-scale total USD amount for active challenge payments on
-   * that billing account.
+   * @returns Payment-scale member-payment amount for active challenge payments
+   * on that billing account.
    */
   private async getPersistedChallengePaymentTotal(
     tx: Prisma.TransactionClient,
@@ -571,7 +572,10 @@ export class WinningsService {
     billingAccountId: number,
   ): Promise<number> {
     const payments = await tx.payment.findMany({
-      select: { total_amount: true },
+      select: {
+        gross_amount: true,
+        total_amount: true,
+      },
       where: {
         billing_account: String(billingAccountId),
         currency: PrizeType.USD,
@@ -584,7 +588,12 @@ export class WinningsService {
     });
     const totalAmount = payments.reduce(
       (sum, paymentRow) =>
-        sum.plus(new Prisma.Decimal(paymentRow.total_amount ?? 0)),
+        sum.plus(
+          resolveChallengeMemberPaymentAmount({
+            grossAmount: paymentRow.gross_amount,
+            totalAmount: paymentRow.total_amount,
+          }),
+        ),
       new Prisma.Decimal(0),
     );
 
diff --git a/src/shared/payments/challenge-payment-amount.util.ts b/src/shared/payments/challenge-payment-amount.util.ts
new file mode 100644
index 0000000..db26b32
--- /dev/null
+++ b/src/shared/payments/challenge-payment-amount.util.ts
@@ -0,0 +1,50 @@
+import { Prisma } from '@prisma/client';
+
+type PaymentAmountValue = Prisma.Decimal | number | string | null | undefined;
+
+export interface ChallengePaymentBudgetAmount {
+  grossAmount?: PaymentAmountValue;
+  totalAmount?: PaymentAmountValue;
+}
+
+/**
+ * Converts a persisted payment amount to a Decimal when it is finite.
+ *
+ * @param value Raw amount from a finance payment column.
+ * @returns Decimal amount, or `undefined` when the value is missing or invalid.
+ * @throws This helper does not throw for missing or non-finite values.
+ */
+function toDecimalAmount(
+  value: PaymentAmountValue,
+): Prisma.Decimal | undefined {
+  if (value === null || value === undefined) {
+    return undefined;
+  }
+
+  const amount = Number(value);
+
+  return Number.isFinite(amount) ? new Prisma.Decimal(amount) : undefined;
+}
+
+/**
+ * Resolves the member-payment amount that should be used for challenge budget sync.
+ *
+ * Challenge payment `total_amount` values can include the billing challenge fee
+ * for older or external callers, while `gross_amount` is the member-payment
+ * amount before markup. Billing-account lock/consume rows must be based on
+ * that member amount so the markup is not applied a second time. Rows without a
+ * valid gross amount fall back to `total_amount` for backward compatibility.
+ *
+ * @param payment payment amount fields from a finance payment row.
+ * @returns Decimal member-payment amount for billing-account synchronization.
+ * @throws This helper does not throw for invalid payment amounts.
+ */
+export function resolveChallengeMemberPaymentAmount(
+  payment: ChallengePaymentBudgetAmount,
+): Prisma.Decimal {
+  return (
+    toDecimalAmount(payment.grossAmount) ??
+    toDecimalAmount(payment.totalAmount) ??
+    new Prisma.Decimal(0)
+  );
+}