help figuring HP washing math numbers and cost.

Seems correct, though you can save some by doing regular HP washing on some of your AP (50 levels from 150-200 = 250 AP) Which IIRC are 54 HP each, for another 13500 HP.

Or maybe that's part of the reason it's only 57500 HP from MP washing.

And you didn't count resetting 496 base INT into STR. I suppose that part could be skipped if we actually get AP-resets.

thing is, assumming the above, and 15k hp at level 200:

69000 hp from washing
15000 hp from leveling
15000 hp fom leveling with int

so that's a total of 100k at 200, this is calculated assumming you can't reach 200 before legend, which in my opinion is very true, considering half the AP will be invested in INT, and the other half on MP, and the plan is to use the AP reset from legend (if it comes) to get 500 str from int. and not have to pay for those 500 resets. i even consider 150 to be a far shot but meh, not me doing it.

(above numbers are taking into account 1.2x hp multiplier)

but the above would be correct then? if you have any other ideas on how to reduce the cost, do tell, ofc, this will be modified on later levels, since level 1~100 will also add a nice amount of MP, which can be used for the cheaper HP washing with ap from 150+