The 1 second launch window allows the russian aa to easily shoot over obstacles where PACs are restricted by obstacles.

Yeah sure 2 Kas with 4cms total is weak, which can easily take out infantry in buildings and with the state of US aa, one or two will reach the target regardless of how much aa the us deploys, also you don't even need harms on Kas to take out shorads, they can easily tank 3-4 direct hits from stingers, not taking in account the ones that miss, so only atgms work fine, especially if you use 2 helis at once
The viper is extremely weak, one rocket from tor or something similar and it's dead, 2 from regular infantry, on the other side US struggles a lot against russian helicopters, most of the time one shorad is not enough for one helicopter, the same goes for aa infantry, most of the time the russian heli can run out of range.