Thanks! I'm thinking about removing the reward fund percentage completely because I realized that it can't be calculated based on a value from which the reward has already been subtracted. Maybe it would be better to show a percentage for how much of the total pending rewards goes to the user.

The calculation of a correct value is a bit more difficult than one might think, because of the SBD payout. All rewards come in SBD (worth of 1 USD) but the totals in the blockchain are measured in STEEM. I will think about all this when I find time in the coming weeks... :)