When purchasing guild building cost bonus, percentage only increased 4%. Why?

[Alisha.Banshee]

I just purchased a guild building cost bonus and our percentage went from 26% to 30% when it was supposed to be a 5% increase. Am I to assume that it is a rounding problem? Do I need to submit a ticket?

Thanks,
Alisha

[Lys]

The way the Health Regeneration, Energy Regeneration, Upgrade Time, Reduced Cost, et cetera bonuses work (Basically all of those that aren't a % boost to unit strength or Raiding Honor gain %) is that the more you get of that bonus, the less of an impact they have. The technical term for it always eludes me when I need to use it, but here's the breakdown.

Because you already had 26%, leaving you a base of 74%, that 5% came out of the remaining 74%. That comes out to 70.3%, or another 3.7% reduction. So, it shows you as having a 30% now.

Basically, the higher your existing boost, the lower the impact it has. I went from 39% to 42% with another guild upgrade, which was only a 3% boost for me. Just how those boosts work.

[Krissy]

It's like buying a new shirt listed for 50% off and then using a 50% coupon at checkout. You don't get it free. No 50+50
You get 50% off then 50% off of the reduced price. So a hundred dollar shirt would be 25 bucks.

[Valid or]

Diminished returns I do believe the term is called. It's the same for all bonuses.

[Lys]

Diminished returns I do believe the term is called. It's the same for all bonuses.

This. I never remember the bloody word when I need to use it. It also prevents the whole issue of what happens if you end up with 100 + % in reductions, because then you get into the whole issue of invalid data from having, say, 110% reduced health regeneration, meaning theoretically you gain HP with a negative timer. Real nasty to deal with coding-wise. This way, one can approach 0, but never truly reach it (or in this instance, -100% on the timer).