It still doesn't matter. It doesn't solve the problem. A chance to take lower damage is never the solution to this kind of problem because the problem is that the damage is too high. There's a reason mitigation is the best way to survive, not avoidance. If Mountain Buster's damage is too high to deal with, a minor chance to reduce it some of the time is not going to do anything other than allow a small chance to win through luck. All those times where you don't parry it, nothing is changed. If you've then sacrificed EHP in exchange for avoidance, you've actually made yourself weaker against this particular threat rather than stronger. You can never force or guarantee a parry, and the returns on dex aren't even good enough to make a serious difference, so this isn't the answer. The only solution to surviving Mountain Buster is to get more HP or more guaranteed mitigation. Since the latter is pretty much impossible at the moment due to the lack of options for raising static mitigation, there's only one answer: get more HP.