There have been a couple of FFIEC statements since the April 2020 statement that you linked.
Interagency Safety & Soundness Examiner GuidanceFFIEC Statement on Loans Nearing the End of Relief PeriodsThe second one, in particular, seems to say longer-term accommodations will have to be treated as TDRs, but I would be talking to my accounting firm. From the second link:
Financial institutions must follow applicable accounting and regulatory reporting requirements for all loan modifications, as the term "modification†is used in U.S. generally accepted accounting principles (GAAP) and regulatory reporting instructions, including additional modifications made to borrowers who may continue to experience financial hardship at the end of the initial accommodation period. This includes maintenance of appropriate allowances for loan and lease losses (ALLL) or allowances for credit losses (ACL), as applicable. Financial institutions may refer to regulatory reporting instructions, 17 section 4013 of the CARES Act, “Temporary Relief from Troubled Debt Restructurings†(section 4013), and the “Interagency Statement on Loan Modifications and Reporting for Financial Institutions Working with Customers Affected by the Coronavirus (Revised)†(Interagency Statement)