Is it possible that he is slightly over sizing the heat pump to get the needed heating btus?

When he gave me the sheet and pointed out that it would cool to 75* on a 95* day. I asked him what if I wanted it to cool to 72 on an upper 90's day and he said it should do that. He said the 75 on a 95 was basically a "worse case" scenario day. Like if we had people over and there was cooking in kitchen and what not.

I hope this guy isn't full of crap. He is actually my best option so far. (And no, he is not the lowest bid.)