Curious how beneficial HP washing is...

Even if the act of washing makes no sense for Magicians (I agree that that high of a ratio is too ridiculous), putting those 19 points between 197 and 200 as a lukless Magician still makes more sense than pumping MP or LUK, in my opinion. Sure, with the extra luk, zhelm, and +1 HT pendant, you can start scrolling some nice Maker'd shoes or overalls, but that's not too much of power boost, which, in the end, doesn't really matter.

What matters at bossing? The stronger ArchMage who dies to a hit or the slightly weaker one who can take the hit? Pump those 19 into HP.

I think if you want HP close to 200, you're better off scrolling a good Int Bosshunter Gi, (White Scrolls, amirite?) and wearing a Naricain Pendant. Getting that sort of HP by washing or placing AP in HP would be very counterproductive.