Buyer's question at signing

A recent buyer asked us at signing (a day or two prior to closing):

“I’ve noticed that the fees charged by my loan officer are about $1,600 more than my Good Faith Estimate. I recall only being charged 1% loan origination. Is there any explanation for this?”

What are the re-disclosure laws (both state and/or Federal)? Obviously, this buyer was a bit under pressure and did not want to create waves to delay the purchase.