Is there a provision in the contract for adjustment?

If not, he's on the hook, but if his price was fair to begin with, and
you think he's incurring additional labor and removal expense, it
seems fair to compensate him.

Some contractors likely build a significant cushion for unanticipated
extras; I'd prefer to deal with a contractor who was honest with his
estimate, with some acknowledged flexibility down the road where
necessary.

Good luck.