[Gandalfa82]

Lol when there's a 10, 13, 15, 17 - naturally we think they mean 10%, 13%, 15%, 17% because those are sensible values. But they could, following the habits of the developers, mean 10 in 1000, 13 in 1000.... or 10 in 50, 13 in 50, etc. Lol. It could even be the mean of a Poisson distribution dictating how many $ a user ought to spend on average before a +9.

Have not thought about those ideas. So could be those.