Hello mathemagics specialists, I have two quick questions about Improved Healing foci on items, I assume they work exactly the same as Improved Damage type ones ? 1. A random roll of X% per direct heal, X being between the 1-Y margin where Y is the upper limit displayed in the focus description ? 2. The 5% malus per level above the cap is not a flat -5% applied to Y, but means, your focus becomes inactive 20 levels higher ? To take a simple example as I am on TLPs, the Yaël range item for priests with Improved Healing III has Y=20 (1 to 20% stronger direct heal per cast) and has no effect at all anymore when you reach level 80 (theoretically speaking and not taking into account healing AAs) ?

Also note that the focus is based on spell levels not player levels. If you're still casting old spells the focus still works to full effect even if you've way out leveled it.

It's not 1 - Y, it's Z - Y. Z being base1 and Y being base2. So looking at Improved Healing III, slot 1 has a base1 of 1 and a base2 of 20. Which means the focus effect will be a number between 1 and 20. But there are spells where base1 and base2 are equal which results in no RNG and there could be spells with a higher base1 (or even lower!) that changes the range of numbers.

I don't think there are any focuses with a negative base value, but yes using an example from current heal focuses, the Raid version is 68% - 100% and the group version is 55% - 75%. When comparing focuses like that the norm has been to average the 2 numbers, so for the raid version you get an average value of 84% and the group version has an average of 65%. On TLP's you probably won't encounter too many like that for a while since they didn't start upping the base value's until later expansions.

Thanks for the precise info ! I forgot to mention mana preservation foci, do these apply the full base value or do they also roll in an intervall as Improved Damage and Healing types ?

The do exist, usually in the form of mob or zone debuffs, that are generally not supercommon. One example that is actually tied to a buff, is the cleric Vow line: [43105/4615] Vow of Vigor Rk. III Classes: CLR/101 Skill: Alteration Mana: 530 Target: Self Resist: Beneficial, Blockable: Yes Focusable: Yes Casting: 3.5s, Recast: 1.5s, Rest: 1.5s Duration: 72m (720 ticks), Extendable: Yes, Dispelable: Yes 1: SPA 125 Base1=-25 Base2=-25 Max=0 Calc=100 --- Decrease Crit Healing by 25% 2: SPA 85 Base1=43108 Base2=200 Max=0 Calc=100 --- Add Melee Proc: Vigorous Strike III with 200% Rate Mod [34198/4561] Vow of Vehemence Rk. III Classes: CLR/98 Skill: Alteration Mana: 750 Target: Self Resist: Beneficial, Blockable: Yes Focusable: Yes Casting: 3.5s, Recast: 1.5s, Rest: 1.5s Duration: 72m (720 ticks), Extendable: Yes, Dispelable: Yes 1: SPA 125 Base1=-50 Base2=0 Max=0 Calc=100 --- Decrease Crit Healing by 0% to 50% 2: SPA 85 Base1=34201 Base2=200 Max=0 Calc=100 --- Add Melee Proc: Vehement Strike III with 200% Rate Mod Info included there to show the difference in Base1 and Base2 values compared to standard focus effects. As you can see, on Vigor, Base1 and Base2 are equal, to give it a flat modifier, whereas the older Vehemence has a range of -50 to 0. Mana preservation foci function the same way the improved damage/healing focus effects do: [2342] Mana Preservation I Target: Self Resist: Beneficial, Blockable: Yes Focusable: Yes Casting: 0s Duration: 3.3h (1950 ticks), Extendable: Yes, Dispelable: Yes 1: Decrease Spell Mana Cost by 1% to 10% 2: Limit Max Level: 20 (lose 5% per level) 3: Limit Spell: Exclude Complete Heal 4: Limit Type: Exclude Combat Skills