From what I saw (and failed to notice when I read the description the first several times) is it appears to be an amount of MP generated upon an evade. Which I mean... that's good for the times you'd be using Featherfoot anyway but it's not like it's a Refresh effect or anything.

EDIT: I think it was 38MP from Featherfoot II? I only really looked at the difference once. @645MP it's not like I was running dangerously low...