Revitalize number bugs: stacks multiplicatively with self and doesn't count base when bonus triggers

I was playing around in practice tool seeing what counts for Revitalize and what doesn't, and I found some numerical bugs.

Here is how to reproduce the bugs. Nami with 6 rylai's, level 9 with 100/2789HP. No AP in runes, precision primary (press the attack, triumph, alacrity, coup de grace), resolve secondary (mirror shell and revitalize).

Cast Ebb and Flow on self.

Gain 370HP. Base healing: (185 + 450x0.3) = 320HP Expected total with bonus from revitalize: 320x1.15 = 368HP If they stack multiplicatively: 320x1.1x1.05 = 369.6HP Actual bonus healing: 50HP Bonus healing recorded in stat bar: 34HP

I think what's happening for the recorded bonus healing is it's treating the bonus and the extra bonus (for <40% hp) separately, it's calculating the extra heal from the extra bonus (in this case 32HP), then multiplying THAT by 1.05 to come up with it's number (instead of the original 320HP). (When Ebb and Flow is cast on self while at full HP, Bonus healing recorded in stat bar is 16HP, as expected)

Replace one of the rylai's with an ardent censor (+10% heal and shield power)

Gain 399/400HP (varies) Base healing: (185 + 435APx0.3) = 315.5HP Expected total with bonus from revitalize and censor (additive): 315.5x1.25 = 393.75HP Closest way of stacking that I could find: 315.5 x 1.1 x 1.15 = 399.1HP That is, it appears that ardent censor stacks additively with the normal bonus, but the extra bonus for <40%hp stacks multiplicatively with them.

Replace 2 more rylai's with mikael's and redemption.

Ebb and Flow: Gain 431HP Base healing: (185 + 285APx0.3) = 270.5HP Expected total with simple additive scaling: 270.5x1.55 = 419.275HP Closest way of stacking that I could find: 270.5 x 1.1 x 1.45 = 431.44HP (For reference, here are other ways of stacking: 270.5 x 1.55 = 419HP, 270.5 x 1.1 x 1.05 x 1.4 = 437.4HP, 270.5 x 1.15 x 1.45 = 435.5) Healing assuming no revitalize: 270.5 x 1.4 = 378.7HP Actual bonus healing from revitalize (i.e. as compared to no revitalize): 431 - 378.7 = 52.3HP Recorded bonus healing from revitalize: 39HP

Use redemption while at <100HP

Redemption active: Gain 491HP Base healing: (10+20x9) = 190HP Expected total with simple additive scaling, treating revitalize as separate to "heal and shield power": 190 x (1 + 0.15 +0.4 x 3) = 433HP Expected total with simple additive scaling, treating revitalize as a kind of "heal and shield power": 190 x (1 + 0.55 x 3) = 487HP Following the pattern of previous calculations: 190 x 1.1 x (1 + 0.45 x 3) = 491.15HP Actual bonus healing from revitalize: 491 - 190 x (1 + 0.4 x 3) = 73HP Recorded bonus healing from revitalize: 45HP

So, it seems that the extra bonus from revitalize (for being under 40% HP) is being treated specially. For abilities and items, it's stacking multiplicatively with normal "heal and shield power" (which the base boost of revitalize stacks additively with).

Next I wanted to test lifesteal. Keep same nami, just buy new items (practice tool ftw): 3 frozen mallets, 2 mercurial scimitar's and a bloodthirster. I will hit lvl1 Red Brambleback (Red Buff), while at <100HP

I hit it for 457 damage. Actual healing: 202HP Expected base healing: 457 x 0.4 = 182.8HP Expected total with simple additive scaling: 182.8 x 1.15 = 210.2HP Closest way of stacking that I could find: 182.8 x 1.1 = 201HP Actual bonus healing from revitalize: 202 - 182.8 = 19HP Recorded bonus healing from revitalize: 18/19HP

What about hitting when above 40% hp? I hit for 457 Actual healing: 183HP Expected base healing: 457 x 0.4 = 182.8HP Expected total with simple additive scaling: 182.8x 1.05 = 191.94HP Doesn't look like we got any bonus at all. Recorded bonus healing from revitalize: 9HP Expected bonus healing from revitalize: 182.8 x 0.05 = 9.14HP

So, it seems that for lifesteal, you never get the bonus 5% healing, even though the stat tracks it as if you do while you are above 40%hp. Again, the additional 10% extra bonus for <40%hp is treated differently.

I will update this tomorrow with stats on how it stacks for abilities when both the caster and the target have revitalize.