Progress reports and final reports serve two different purposes and are currently managed through two different systems.
Annual progress reports are written for program managers, who must approve them for the next year of funding to be released. The last year of the project is often a no-cost extension, and currently, PAMS does not require a progress report for a project in a no-cost extension.
Progress reports will be requested by PAMS 120 days before the budget period end date for all but the final year of your project. Therefore, you will not be able to submit a progress report until PAMS asks for it.
If you have been granted a no-cost extension, you are not required to submit a progress report. However, some PIs highlight their progress by e-mailing a brief, informal report to the ASR program managers.