Progressive hotness plays one clip for each level a card has.
So if a card has all five level types it will play one clip of each from no nudity up to x rated.
Now if the card does not have all five levels I have heard it may duplicate some levels.
So if a card has no nudity, full nudity and explicit you may get a couple of clips of full nudity playong.
I have never used progressive hotness so I cannot confirm.
I do believe it was more for use in deskbabes where there are scene numbers, but my memory could be tricking me. ;-D