The problem with relative numbers is that they provide a mechanism to increase absolute numbers without impact to the percentage. Thus, “fewer ads” today could be more tomorrow if we consider that we don’t know the absolute number
Regardless I think the problem is ads on a site like Twitter aren't really worth paying to skip. I have Spotify premium because it really is annoying to listen to an unskippable audio ad in the middle of a playlist, but scrolling past a promoted tweet is not much different than scrolling past a tweet by a follow that is about something I do not care about.