diff --git a/apps/web/config/default-values.ts b/apps/web/config/default-values.ts
index d83ae9d..d398ec7 100644
--- a/apps/web/config/default-values.ts
+++ b/apps/web/config/default-values.ts
@@ -111,7 +111,7 @@ const defaultValues: CalculationValues = {
   quoteUrl: null,
   rate: null,
   recalcWithRevision: false,
-  redemptionPaymentSum: 0,
+  redemptionPaymentSum: null,
   regionRegistration: null,
   registration: null,
   registrationDescription: '-',
diff --git a/apps/web/config/schema/values.ts b/apps/web/config/schema/values.ts
index e764341..1c6fc82 100644
--- a/apps/web/config/schema/values.ts
+++ b/apps/web/config/schema/values.ts
@@ -98,7 +98,7 @@ const ValuesSchema = z.object({
   quoteRedemptionGraph: z.boolean(),
   rate: z.string().nullable(),
   recalcWithRevision: z.boolean(),
-  redemptionPaymentSum: z.number(),
+  redemptionPaymentSum: z.number().nullable(),
   regionRegistration: z.string().nullable(),
   registration: z.string().nullable(),
   registrationQuote: z.boolean(),