Only notable discrepancy in tier cost, is T1. Which balances out when all tiers are built, in total. Largely an indirect result of Ost T0 being basically entirely useless as opposed to Cons building from Sov T0.
Aside from that, there are three fundamental non-cost/buildtime discrepancies.
-Onfield time for Pios while Battlephasing (which ranges from roughly 30s to 50s)
-ATnade/Molotov upgrade (arguablyna result of free Oorah and Merge)
-The spread of units in respective tier buildings.
Otherwise the cost/buildtimes of tiers are quite equal.
Ok. So half price seems to be alright.
The "cheap backtech" would be a small change with big impact, nao pls Relic do it!1!!!111!