I understand. Still, I believe that for two above reasons (1. less manpower OKW will have to spend on infantry; 2. those extra abilities including retrat) it should cost as much as other anti tank guns.
Making RW to "reduce" the manpower of OKW is a step in the wrong direction because their that will force allies to use WC51/m3 to gain advantage.
If OKW need less manpower simply lower the starting manpower. (alternatively increase cost VG or time to build.)
RW does not "extra" abilities camo comes at vet 1 and it needs to reach vet 3 to even get a first strike bonus.
If you want to talk about "extra ability" you can look at cheaper M-42 with vet 0 camo that can move/vet 0 first strike bonus/canister shot.