Flat 5,500 or 2.4% on a 460k purchase, for different scopes of work

Two written proposals in front of me for the same search.

Agent A: 2.4% of purchase price. On my target range that's about 11,040. Full service, she's been doing this eleven years in the submarket I want, and she volunteered the comps that talked me out of a house I liked last month, which I noticed.

Agent B: flat 5,500, payable at closing regardless of price. His scope excludes showings before I've narrowed to three properties, and excludes what he calls "repair negotiation beyond the initial objection letter." He'll write offers, coordinate inspection, and manage the file to close.

So the spread is 5,540 for the work in that exclusion. I've never negotiated a repair credit and I'm buying a 1972 house with original everything, which is exactly the situation where the exclusion bites.

The other thing bothering me is that both proposals leave the seller-side question open, meaning whatever the listing broker offers gets applied against the fee and I owe any difference. On a percentage deal a 2.4% offer from the seller zeroes me out. On the flat deal a 2.4% offer is 11,040 against a 5,500 fee, and neither proposal says what happens to the extra 5,540. I've asked both. A said it stays with her brokerage. B said it can be credited to me if the contract is written that way and the lender allows it, which he'd confirm in writing.

That answer moves the flat fee from cheaper to a lot cheaper, if it's true, and it makes the exclusion the whole question. I'm not sure I'm the person who should be handling my own repair negotiation on a house of that age.