200 is 10% of 2000, not 5%...

It's a +/- 5% margin of error however. The "within 5%" descriptor can be interpreted in multiple ways: either all classes are within a 5% margin of error of the "goal" DPS (as such, ~1900 is goal DPS and the acceptable range is ~1800-2000) or they're all within 5% of each other (which would mean all classes fall within a tighter realm of a +/-2.5 margin of error wherein the acceptable range is half as big, likely ~1800-1900 or ~1900-2000). This is always one of the problems with using percentages without proper labeling, of course, neither is actually true since Scoundrel DPS tops out at 1600, so they're not even keeping up with either definition of "within 5%".