Opfire (no, not about the draining problem...)

[Wdll]

You are assuming too many things there.

1 M1A1 is not = to 1 T-72s. Just because the M1A1 needs some seconds to fire at one of the two T-72, it doesn't mean that the other T-72 can locate lock and fire in that same amount of time. Also training, where do you put that?
Also, there have been battles in Iraq where the allied tanks were outnumbered, they still annihilated the Iraqi tanks. Even without Opfire.

If you want to get a chance, then perhaps you could force the enemy tanks to fire at something else first.