Mother's Embrace flask charge calculation is wrong

Not the regular minion stability bug. I believe this one hasn't been reported before.

When calculating flask usage with Mother's Embrace, the "40% reduced flask charges used by minion" is MULTIPLICATIVE with regular reduced flask charges prefix on the flasks, instead of ADDITIVE.

Proof:

I used a -40% belt, with -15% writhing jar.

Cost should be: (1-55%) x 20 = 9
Actual chargers cost: 10 per use. I think this is arrived at (1-40%)*(1-15%)*20 = 10.2% => round down to 10.

Also charges used is not impacted by "reduced charges used" on tree, but I guess this is intended? In that case should re-word the notable to "reduced charges used on you".