Now you're scaring me, MsP, since I hadn't heard of anything like that kind of negotiation and I suspect that what you need as start-up is more comparable to what I need than my lab-type colleagues. The process will be what it is, but I hadn't heard of that kind of negotiation except for big STEM labs at R1's.
I hadn't either--and it really is a very bizarre way to handle things, too; I had to include my basic office computer and software in my startup, as well as travel funding and some other things that are ordinarily just a given part of the departmental budget at most places. I would be very surprised if anything like this happened to you, Polly. I only raised it because it's one more example of things that can unexpectedly slow down the the process of actually getting the formal written offer.