Invention: Recharge Reduction

[Krulton]

I am not sure if this has been posted before or if it is an actual bug...

I have slotted a few low level Invention: Recharge Reduction enhancements (level 10 and 15, I'm low level what of it! :p) and the percentages seem to be off or I am not understanding how they work.

I currently have 3 rank 15's slotted in the Chronos power, each of which give a reduction of 19.2%. While the total percentage showing on the pop-up tool-tip is 57.6% the 90 second cool down is changed to be only 57.11 seconds which is a reduction of 36.5% I have noticed the same with the rank 10's which are 11.7% and 3 of them only lowered the power to 66 seconds when the tool tip showed the percentage reduction as 35.1 it should have been 58.4 seconds.
This is the only type so far that I have noticed that the tool tip percentage did not match the actual reduction. I have a few damage and accuracy ones slotted in my offensive powers and those numbers match the percentages shown in the tool tips. As well as the the 3 rank 15 DO's I have slotted in stamina recovery show the correct increase for the percentage shown.

I remember from a long time ago that there was diminishing returns on the enhancements but the tool tip usually indicated that the percentage was different as you slot more of the same type. That may be what's happening here but I am unsure due to other enhancements don't seem to be affected or are showing the correct info on the tool tip.

[arcane]

90 seconds x ( 1 / 1.576 ) = 57.11 seconds. 
 

Working as intended

[srmalloy]

Endurance and Recharge reduction enhancements are inverted. Enhancements like Damage or Accuracy have a multiplication effect -- base * (1 + enhancement) -- so two even-level SOs, 66%, give you base * (1 + 0.66). Recharge or Endurance is base / (1 + enhancement), so the same two even-level SOs give you base / (1 + 0.66), which is ~60% of base. Each increment of recharge reduction gets you a smaller decrease -- 50% to 100% gets you 10% better reduction, 100% to 150% gets you 6.7%, and so on. Even 400% recharge reduction only gets the recharge time down to a fifth of base, so a power with a ten-minute base recharge would still take two minutes to recharge, and you'dhave to put an awful lot of work into doing it.

[Krulton]

OK, I'm just using the wrong calculation. My apologies.