diff --git a/src/lib/invoice-generation.ts b/src/lib/invoice-generation.ts
index 448efc6..b7c9eac 100644
--- a/src/lib/invoice-generation.ts
+++ b/src/lib/invoice-generation.ts
@@ -15,11 +15,12 @@ export interface GenerateInvoiceResult {
   invoiceNumber: string;
 }
 
-// Round hours to the nearest 0.6 (per firm policy: tenths of an hour rounded
-// up to the nearest 6-minute increment, capped at a 0.6h granularity).
+// Round hours UP to the nearest 0.1 (6-minute increment), per firm policy:
+// any time worked is billed in 6-minute units, with a 0.1h minimum.
 export function roundHoursToSixTenths(hours: number): number {
   const n = Math.max(0, Number(hours) || 0);
-  return +(Math.round(n / 0.6) * 0.6).toFixed(2);
+  if (n === 0) return 0;
+  return +(Math.max(0.1, Math.ceil(n / 0.1) * 0.1)).toFixed(2);
 }
 
 export async function generateInvoiceForClient(args: GenerateInvoiceArgs): Promise<GenerateInvoiceResult> {