U should have known the cap before interviewing

Sometime company gives a wide range like 85~120K but they never give out the 120K, unless you one of the kind. They just use that big number to attract candidates. I always ask for the most they are willing to pay or I won't go for interview because it would be waste of time for both parties. If you were comfortable enough to accept the offer, then that is about it. You can of course reject it if feeling you worth more and can find better one.