Okay now you have lost me.
As far as I remember, cost for osther teaching was only reshuffled main thing making BP2 costing more to ok make tier 4 viable.
If your relating this to grens (tier one) I don't know what you mean by cost increase. Please explain.
Edit: I assume you were relating to osther.
basic example for ukf it takes 30 + 115 to reach tanks , osther have 40 + 90 + tier 1 tier 2 and tier 3, so tier 2 and 3 are extra cost that are built in weapon and nade upgrades (like ukf can pay more for nades and weapons)