I agree with @J Scott and @Michael P.
However, I do know what its like when your the GC and your sub comes in with a change order. Of course he is going to kick that cost to the owner. It might be worth talking to his electrical sub and seeing just how much more his bill cost, and why. Sometimes unforeseen things happen, and there has to be some flexibility in your budget for that. I would dig a little. Maybe the electrician is part of the problem, and it could be solved with a simple phone call.
I will say that my personal opinion is this is a very typical contractor, and its a classic scenario. Contractors are always late, and always cost more than they are supposed to. That is going to happen again, I can guarantee it. 1900 bucks isn't worth going to court over in my opinion, so I would probably just make his life difficult until he drops it. One letter from a lawyer scares the heck out of these guys.
Where in Upstate? Hopefully not my hometown of Gotham City..... I mean Binghamton