Reason to make it single call-in:
*720MP and 260 Fuel for a medium tank investment is too high.
*Almost impossible to replenish any T-34/85 losses since next call in still needs 720MP and 260Fuel.
*T-34/85 isn't that great for a initial cost of 260Fuel and it's doctrinal unit.
*Why only the T-34/85 suffers from a double call-in penalty while all other armored vehicles are not?
