While Panzer IV has a little more fuel cost, it is available at tier 2. Soviet T-70 and SU-76 at tier 2 is no match for the Panzer IV. So basically Germans can bring a stronger tank earlier in the game.
That's not how that works, Soviet and Wehr teching don't match up one-to-one. While the Soviet's T4 and Ost T3 have different tier numbers, they cost roughly the same amount of time/fuel to get to, so they're equal to each other. For EFA tech:
Sov T0 = Ost T0
Sov T1 and T2 = Ost T1
Sov T3 is between Ost T2 and T3
Sov T4 = Ost T3
Ost T4 is unique, its only Allied equivalent is British Hammer or Anvil.