Machine Shop Charges, What is reasonable? Options

[OU8AVW]

So, I dropped off my disassembled engine at a machine shop in DC. First off, this is an incredible shop and talking to the guy let me know he was top notch. He used to build NASCAR engines professionally and has two masters degrees in metallurgy and automotive engineering. He uses sonic frequencies to re temper parts after they are machined> Crazy stuff......
Anyway, I drop off my stuff. First he does a pair of 2.0 heads for me. For this he charges me $400 for the work. Really just cleaning them up, machining the seats and installing new guides, springs and my supplied valves. Not a bad deal and it was done in three weeks. They look fantastic. At this point he tels me $250 or so to balance my engine.
Then I deliver my engine parts. Case, rods, cam, ect. I also delivered a doner set of parts, essentially a short block and pistons/jugs. I also delivered a full gasket and bearing kit. My request: find the best parts to make a complete motor then balance everything and get it ready for assembly. I would take it from there. I sent him a $500 deposit to start
Good plan right?
It's now been two years. No a big deal as my car is still in pieces and I've been taking my time collecting parts.
Fast forward to now. Still not ready and he's been telling me that it will probably be another $1500 to get my parts done as requested. I have asked him to communicate exactly what he plans to do to my engine for $2000. Remember, these are all stock parts and he has not communicated any significant problems because he hasn't gotten that far on the project.
What should I expect to pay for a checked over and balanced motor? I think $2k is really high. especially when he wants another $800 to assemble it....What questions do I ask to sort this out?

Thanks in advance