So according what you told 1st level up could cost up to10850 coupons. That high cost would make % tactics too expensive for about 99,999% of playerbase. That spends money into this game. Not to mention FTPs. I can't even dare to imagine how much higher levels would cost and how many of those levels there are...

In addition, it's worth would be different for higher powers, since they would end up getting lot more power at same levels than mid- and low powers. This wound just end up making high powers get even more ahead of others and breaking game's balance even further.

Result: No, thank you. Game has finally started to get over level 13 refinements, runes & etc. We don't need anything like this even since majority voted against it when it was first talked about.