If you have AC on a 100a service and it made it through a load calc for a service that size, it is one small house! Or they have few if any other loads.
As far as that table, if it were a single family, with no way to go up, or out, and the calc was ok, maybe. But you would not be doing your customer a favor by sticking to the minimum. Think about what could be done with the house if it had a 125, or 150A.
"Well - I oughta....." -Jackie Gleason