Is rev share % absolute or incremental?

I just had a look at the brightshare program and noticed their examples in which they start their rev share at 25% and from certain points it goes up to 40%. Than they give an example of the net revenue and, because it has a certain value, take 32% of it as your earnings. So they do NOT calculate it incrementally (take 25% of the first share, 28% of the second, etcetera).

Is ‘absolute rev share %’ the rule in this industry or is it ‘some do some don’t’ in this case?