I can't say for sure, as I recall NACA describes this process in detail on their website.
I believe NACA is seeking rock solid assurance that the repairs will be made (and FHA would do this as well). This is for your protection. So they will want to see the bids, contracts and funds for the repairs in order to clear you to close.
HAND monitors the execution of the repairs. They will expect the follow up inspection showing repairs complete, and HAND approval is needed to release the funds to the contractor.
This is all needed where the seller doesn't complete the required repairs before closing, which is what I believe should happen here.
