The load calculation for this house came out to 260 amps - I'm assuming from the meter we will feed two panels with a 150 main in each

Or even two 200A panels. This would be a 320/400 amp service. 400A, 320 continuous.
In my opinion there is no reason to with two 150's. Two 200's cost nearly the same.

It depends. Who did the load calculation... the homeowner?