jerc I guess you don't know SBT
Nah, I get that this guy basically is a deity of ut, who invented fragging as a thing and we mere mortals are just his plaything.
Argument is that one can dodge ball either with good enough reaction, better ping or both (that's assuming, that shot is not pointblank - and even with pointblank-shots I've experienced misses) and can be repeat that several times in a row - that generally will lead to diminishing in overall accuracy of guy who fired a shot/s. Yes, there's also different things that influence the outcome of your shot (map size and design, how packed server atm, your ping, how skilled/unskilled your opponents are etc), but that's another theorycraft story.
As for multikills with balls - I'm not sure how stat system calculates accuracy for that, but my guess is that counts as 1 shot 1 hit (as it should, since those 2+ ppl are just collateral dmg of 1 specific instance of hit).