Small projects need an itemized summary by contractor. Large projects need the full procurement file plus invoices, and time-and-materials contracts need proof of close oversight.
All small projects must still comply with procurement rules, and FEMA reviews any small project using noncompetitive, time-and-materials or cost-plus-percentage contracts.
Source: PAPPG Table 15.
Build the procurement file as you go. Selection memos and price analyses written after FEMA asks for them rarely hold up.