When comparing across various formats, it may be best to calculate a "standard candle" score, acting as if there were no powers (nor negs, though in cases like this that's unlikely to be a factor) nor bouncebacks. None of the PACE NSC scores survive above 700 when those two things are deducted.
The 780 by Maggie Walker at VCU Spring is likely the highest score ever achieved on such a metric, and if memory serves me, whoever was moderator for that game attested to the fact that MW just spaced out on the two bonus answers they missed, keeping them from a super-perfect game.
Painfully, I also can't help but note the final of PHSAT 2010
, wherein Hunter put up 765 (700 without powers) against us.