Discovery work or not? Replacement of panel tied to installation of new circuits

[Patrick M.]

I have a contract with a contractor that states the following (as part of the larger contract: "Each kitchen will have five circuits installed (fridge, micro, 2 at counter, and one installed but not activated for disposal)"

He didn't calculate the fact that these additional circuits would require a larger panel, and he has added the cost of materials and installation to the amount owed. He's claiming this is discovery work and should thus be billed separately.  He had opened the old panel prior to bidding on the project and spent ~half hour determining what was needed in terms of new circuits as part of our kitchen remodel.

My opinion is that he should have done the math prior to giving me his estimate/contract and included the panel upgrade (and the associated costs) from the outset.

Thoughts?

Thank you