And how is an OKW player supposed to do that?
With OKW I have plenty of matches I just float MP with nothing to spend it on. Now I could invest 30 fuel into a 223 and after 4 minutes get the fuel floating to sustain tank losses in the late game.
A OKW can not do that even with 223, the 223 is a more expensive versions of the Opel in manpower while costing an extra 30 fuel, it is not caches.
In addition its probably the only vehicle that has to pay manpower and fuel for an upgrade, most vehicle pay munition for upgrades.