There is no equipment that is listed with the use of 90 deg terminations. Granted there might be lugs in the equipment with a 90 listing, but the equipment is not listed with lug rated 90 deg, just 75 deg.
So, you are right, you need to use the 75 deg column at most. At 100A and below, if you don't know the equip lug temp, you need to use the 60 deg column by default.
