Chart that shows cost of each upgrade for allies and skills

Has anyone made a chart that shows how much it costs to upgrade each skill level or ally and what benefits you get at each level?

I'm on iOS so it costs an awful lot of gems to upgrade an ally or skill to level 10 or 11. I'm debating upgrading my kunoichi's flash bomb skill above 10 (8 second stun, 120 lifesteal) because I'd like the stun to last longer, but it costs 30 gems to go from 10 to 11 and it only gives an additional 6 points to lifesteal so unless I know I'll get an increase to stun later on it seems like I can easily waste 90-100 gems and get almost no benefit. If stun can't be improved by more than 8 seconds, I would have stopped upgrading that skill when it reached level 8 because if my memory is correct it was level 8 = 8 sec, 60 lifesteal and level 9 = 8 sec, 85 lifesteal.