The gemshop wants us to believe, that 5 BLC keys were at 625 gems and now are available for 337 gems. Same with 25 keys for 3125 gems.
This is wrong. The prices are calculated from 1 BLC key and then just multiplied. But before the 26% (which are actually 25%) the prices where:
1 key: 125 gems
5 keys: 450 gems (450 * 0.75 = 337,5 gems)
25 keys: 2100 gems (2100 * 0.75 = 1575 gems)
I kinda thought, this is a false display which would make one believe “Oh wow! When I buy 25 keys, I have a discount of 50%!” because 1575*100/3125 = 50.4 (means 49.6% discount) whereas it really is 1575*100/2100=75% (which means 25% discount).