Hi,
I understand the OCD concerns about the number. It would be nice to only deal with intervals of 5 or 10 posts however when there is such a low limit a few posts difference can make alot of difference to users. Increasing it to 20 will not be good for us and will probably result in a drop to 15 at some point. Dropping it to 15 now would be good for us but will limit users a bit more then we would like and as loudawg mentioned, I am sure alot of users here would prefer to be able to earn from an extra couple of posts daily.
It is a careful balance between keeping the forum financially stable and keeping the rewards for members as good as possible. Unfortunately it does sometimes mean that we have to not be so OCD in terms of numbers etc to keep an ideal balance between the 2.
If alot of users feel that the random looking numbers are annoying then in future we can try and round them up or down although it may limit users earnings somewhat.