All of the above posts are pretty much correct, but to add to that, pp would be more accurate on a per-score basis if it worked like tp imo with regards to how aim speed and acc are treated. Your pp from a score isn't too much different from the sum of its aim speed and acc values (a power mean is used to weight the highest value a bit more), which means that most scores that don't give a decent amount of each are almost worthless. In tp, your overall aim/speed/acc values were calculated by putting all of your aim/speed/acc values in order and applying the same decreasing weighting method as is now employed for your total pp. That allowed scores like a low-acc DT FC on mendes (or impressive FCs on low OD nomod maps) to be properly rewarded, whereas the current system makes them seem relatively insignificant. In exchange, the current system allows you to get more pp from your stronger aspect(s) and that probably balances out total pp, but tp's system was certainly better about rewarding you for individual good scores.