Do you have a source for that? This seems like the kind of thing that should be widely discussed among creators, but it's hard to find numbers. (Maybe due to NDAs?). The best I could find the last time this was discussed was this, but it's not a lot of data points and the numbers vary widely: https://old.reddit.com/r/PartneredYoutube/comments/9mj13u/sh...

The numbers posted show premium viewers making more money for the creators per viewer. How much more depends on exactly which of the datapoints you pick, but it's ranging from 35% more to a rather implausible 3600%.