Yes those derp numbers are correct if we find a block at the exact moment you are looking at the derp value which changes by the minute. If it's less than you see on other pools it's because you haven't mined here long term, but you'll continue to get paid on subsequent blocks as well, even if you pull out now. It averages out over many blocks rather than per day or per week or month even. If our pool was 100x larger it would be different and you could do a daily comparison. Luck will be the main determinant of whether you'll end up getting substantially more or less on this pool than if you mined elsewhere, which is much more of an effect than the pool's fee which is zero.