Service Contract Reporting and contracts that span fiscal years.

Had a quick question in regards to SCR. How does one report when the contract action crosses fiscal years. The action in question runs 7/17/20 - 7/16/21. But if the vendor uses the invoices for 10/1/20 - 09/30/21 it exceeds the amount of the previous option and produces an error because of the overage amount. The FAR is silent on this, as well as our supplement, and our procurement and acquisition manuals.