I really question the value you are placing on std deviation.
Take for example Martial Arts and Dark Melee in the mid tier IO table.
MAs WORST result is 6.57. DMs BEST result is 7.03. Yet DM is rated above MA (albeit narrowly) because it is consistant? Consistantly worse maybe.
If a set is on average 30+ seconds behind on each on run just how much valube do you place on the fact that sometimes its only 10 or 20 seconds behind? Your still behind.
There are several sets (TW, Spines, WM, Ice, Rad) who's worse time AND best time are better then DMs worst and best but because they vary between being say 5% worse 20% of the time to 20% better 80% of the time they get a lower rating overall?