I don't think we would want higher prices for higher income either. People would like to see fair prices since the munition/fuel resources are stabilized for OKW. Obers 60 munition LMG for example is a bit too cheap for it's performance and effect on the squad all together.
All LMGs cost 60ammo (except DP-28s because they are considerably weaker). MG34s costed 60 with penalty just like OKW nades costed 30 like all other basic nades.
Let's assume it was justified to increase its price, 120 ammo would be too much. It simply doesn't deal twice as much DPS as other LMGs. 75 ammo would be OK - or 80 but not more.