HP washing calculation

Hi all

I am currently washing and self-leeching an NL and BM together. This is my first time doing this and I was wondering if anyone could help me double check my HP washing calculations and let me know if anything is wrong. This will also be a good reference (in my opinion) for any future washers.

Currently both characters are at Lvl 39 with 39 washes available (checked using discord bot)

I will level from 39 to 50 with about 250 TOTAL int (~80 int from gear, the rest from base)
From Lvl 50 to 150, I will have 300 TOTAL int (100 from gear, ~200 from base)
NOTE : These are conservative estimations, I may have slightly more or less int from mw20 and some additional gear if I can cobble together more.

Basic Calculation :
Total mp gained = (250/10) x 11 + (300/10) x 100 = 3275 mp
Total washes possible = (3275/12) + 39 washes I currently have = ~311 washes

Total hp gained = 311 x 18 = ~5600 hp

Since I will have 3500 base hp by lvl 155, is it safe to say my total hp after washing will be around 9100 ? Are my calculations right?

ADDITIONAL NOTES :
It takes around 6 days to vote for 10 washes (ignoring vote streaks and double nx days). To completely
wash (including resetting the int), it would take 306 days.