Watch back from AD service, have questions

[Vernal]

I bought a pre-loved old-model SEL sub, but it turned out that it was grinding when I wound it, and the crown had been overpolished. I took it in to an AD with a watchmaker I found, and wound up paying $670 for a new crown, tube and overhaul. My questions:

Does this sound like a reasonable price?

I brought it in at the end of Sept. and just got it back today. Does this seem excessive?

All I have from the AD is a credit-card receipt for the total, no mention as to why I gave them $670. Should I insist on some sort of detailed invoice to prove that the watch was serviced? Shouldn't this be standard practice? I was told there was a warranty from the jeweler when I dropped it off, but I was so chuffed about picking up my Hulk at the time I forgot my usual skepticism, especially since I had dropped almost 20k there in a very short period of time. Did I get suckered? I got carried away again when I picked it up, now they're closed for the day and my brain is finally working again.

All in all, I'm trying to decide what to do when I call them tomorrow, and whether I go back or not if I have any other issues (with other watches, as I'm tossing around buying another pre-loved one or two). Should I have sent it to the RSC instead?

They did bring a new Exp 2 42 out of the safe for me (which also kept me from asking logical questions at the time), first time I saw it in person. It's a nice watch but I don't think it qualifies as the "stealth Rolex" anymore. I liked the orange hand, but the dial really looked huge. I'm glad I picked up my 16570 when I did.

Thanks!