I think you potentially have a decent deal with this person, Brian. Someone might do the plans cheaper, but if you know this person is good that’s worth something.
If you choose to go with him, pace about half the money due to him up to plan check with a payment when the building department takes your prints in. Give him the rest when you get approval to get permits. Could be “over the counter” too, but I doubt it.
Check with the building department to find out what the reasonable time for them to process your project is and hold you guy to it.
That’s about how I would do it anyway. I have drawn and submitted house plans three times now with the county. I did one plan check with the city when my client’s architect was dropping the ball. The biggest problem I had with any of my own submittals was getting past the loathsome rookie technicians with the county who kept doling out odd requirements for the pre-submittal process one at a time. I finally lost my temper with them and got with a supervisor who put a stop to it. Other than that it wasn’t bad at all.
Sometimes you have to fend off bogus requirements so experience helps there too. Maybe someone else wouldn’t fight for you as much as you would for yourself.