What are the FHA allowable credits at the closing?

[David Bridgewater]

I know that FHA allows the seller to pay a maximum of 6 credits.

a) Is that in total with the closing cost and loan amount, or can it be applied to just the down payments on the loan?

b) Does the prorated taxes that the seller pays account for a portion of those allowable credits, or is it a totally separate obligation of the seller?

c) What exactly is the seller responsible for paying at closing and does that have anything to do with the buyers allowable credits according to FHA?