Small projects are funded on estimates and close with a completion certification. FEMA adjusts them only for specific reasons. If your small projects together cost more than FEMA obligated, you can request the difference through a net small project overrun appeal.
Actual costs for all small projects (for an overrun), or the completion certification.
The overrun is calculated across all your small projects together, not project by project. Track actual costs on every small project, including ones that came in under estimate.