mana cost display value is incorrect

Im using mace skills, the mana cost is much higher then the display cost.
I also have friend using elemental spells having the same problem.
Either the display value is wrong or the cost value is wrong.
This problem seems be on all my skills. So I bet everyone is effect by this but I could be wrong.


Example one:
My Sunder skill with both my +6 all melee skill says cost 488 mana to use
I have over 750 mana
On full mana it says I don't have enough to use the skill
I even get the blue flash that shows you lack the mana to use the skill

As side note:
I hope the display is the correct value otherwise that's insane mana cost

same here, my lvl 37 shockwave totem tooltip says it costs 937 mana, in fact it cost about 1080 mana (without any support gems, just skill itself)
it always about 15% higher, so i did some passive tree rollbacks
seems Brutal Strength does double penalty on warriors - it reduces your maximum mana AND rises skill cost