The logic behind leveling OCD and how much you can store is pretty irradic. In the beginning the cost is low and the benefits high, but around lev 5/6 it totally flips the other way. Cost go up drastically with little extra gain. but across the board I fail to see some of the logic behind how things go up slow or fast at certain levels. E.g. stack size
LVL Cost Stack size #slots
1 free 1K 7
2 200K 2K 15
3 300K 3K 30
4 2.5M 15K 70
5 7M 50K 100
6 70M 60K 130
7 700M 70K 170
8 800M 80K 200
9 and 10 are similar upgrades as 8.
And there is other things as well. Centrain benefits… E.g. the logic behind epic equipment looks good.
But I think a bit of smoothing on the sizing and upgrade cost (like you did with bank levels) would help…
Regards, Aernoud