Ferocious Roar's mana cost is bugged.

Ferocious Roar is consuming twice as many mana when it has a warcry socket into it.
A level 7 Ferocious Roar cost 36 mana
A level 7 Infernal Cry cost is also 36 mana
So it should at max cost the combined mana cost, so about 72 mana, but in my test it costed 108 to 144 mana, changing randomly. What makes me believe it is a bug.