First of thanks to the quick reply, but this little detail (5% of the toal amount owned) has to be mentioned somewhere!
It is quite a lot after purchasing a 2Mil bundle for 100 gems.

my suggestion:
Well don't make it percentage based then?
What if a player only needs some XP or mats to forge a new hopebringer and doesn't have gems to reset a CD?

It is too much, simple as that.
Limit it in 1 way or another or make sure that new players are aware that it is based on the total amount that a player owns.

Also you might want to look at how Power is calculated.
Some *frontline* fighters pump everything into their equips and nothing into their (mostly only 1) backline unit and can easily own a 3-units formation with more power.

thanks for reading