best cost-efficiency is actually level 80, after that the attributes of most skills don’t benefit that much anymore if they are affordable (i.e. Rank 6 and below skill attributes) while others that benefit more (i.e. Rank 7+ skill attributes) are becoming so expensive that it’s ± impossible to max them at the current point of the game.
It’s nice though, because it’s a tool against hyperinflation since players will definetly sink those silvers into the last 10-20 levels once 100m is medium tier silver till pocket change, actively reducing the inflation.
I for myself have my Heal at level 95 because I didn’t want to spend the points I already had pre-balance into any other attribute that has way less possible damageoutput. The other attributes are mostly at 70 since I’m currently improving my weapon with the silver I earn. Merkabah is left at 50 since the damage-cost efficiency is not nearly enough to consider sinking more silver into it(8,4m for only 420% more overall attack is somewhat poor, maybe if I ever have that money left; meanwhile I’d get 387% more damage if I just max Heal for 3,5m or 453% by putting 5m into Cure level 50->90)…
Higher than 80 is a waste for most skills anyway if you only have 5-10 skillpoints invested into them.