Dealt with the same kind of thing more times than I can count. A dollar bill is about four thousandths of an inch thick, so yeah, it will slide under all sorts of stuff and tells you almost nothing about a high spot. A 3/8 inch dip across a floor is huge, that is not a maybe, that is a fact you can see from across the room with a straightedge and a flashlight. Guys like that are not really measuring anything, they just want a reason to knock the price down and hope you cave. You did the right thing showing him the real numbers, and honestly walking away from the fifty bucks is cheaper than the headache of a guy who argues with a level.

JEEZ. Seven hours of pure chaos sounds about right for Dayton. Loose neutrals are the worst kind of hidden nightmare, one little wiggle and boom, everything's dark. I swear some guys treat a panel like a plate of spaghetti and just call it a day. Good on you for labeling everything, that's the kind of work that actually saves someone a headache later.