Message SAP BIL010 - Error changing from rate category &1 to rate category &2

Diagnosis You changed rate category &v1& without dynamic period control (DPC) torate category &v2&, which is billed with DPC, on &v3&. This change isonly allowed at the beginning of the billing period, &v4&. System Response Processing is cancelled. Procedure Make the rate category change at the beginning of the billing period.