Most travel systems will always look for the number of what you are looking for in the same category. So if there are not two suites available, you will only see one. I just looked at a Hampton Inn and Suites for a date in the future, and it showed suites, but only the suites that they had enough of for the number of rooms I was looking for. They for example only have one whirlpool suite, so any search of more than one room did not show that room.

It's stupid, given they let you choose each room individually, but their system can't handle showing different room types in the select a room tabs for each room, they all have to be the same for whatever reason.