You are very wrong on the armor penetration for the CG 84mm though. When I was in the army (infantry squad leader) we were told never to use the CG on MBT's, maybe maybe if we had good flank shots, but it was generally a bad idea. Instead the CG was used to take out APCs and fortified locations, and the AT-4s were to take out the MBTs.
Yup..the AT-4 has better armor penetration than CG. At least back in 93. I know there are new ammo out for the CG, but then again, the AT-4 has an improved version too that is said to take out any east block tank from the front.