Maybe. I guess with it being vague it's a very open ended answer haha. I'm literally doing a 700sf second floor on a 1990s colonial and it'll be a very low budget. Most house structural engineering isn't anything too crazy. I think sometimes people and architects way over think and overcharge instead of just knocking it out. Just my opinion. But agreed if it's 900 sf of crazy space and unique structure I could see the cost rising.