Is this a change order?

[Ricardo Meza]

I have my personal home in remodel and we added an addition to an existing covered patio with a common roof to the home.  We're adding french doors to this room, a window, new framed walls, ect.  The slab is sloped to the exterior, because is was a patio.  The addition would require this slab to be level for the new flooring.  In my mind, this an existing condition the contractor should have been aware of, and any means to level it, his.  I asked the contractor if he thought he could float the floor, or if he'd need to install a new slab during the initial walk - he didn't have an answer at the time, but he has since mentioned it needed to be leveled.  

My question is, am I wrong in thinking this is not a potential change order, and it should be included with the remodel costs?

The contract does not go into this detail, and it's not specifically included or excluded.  However, my gut is telling me he's going to try a claim that this is extra work.  What are your thoughts?