[Marcello]

"I would think they would run out of ATGMs and other sophisticated AT rounds (sabot, DC-HEAT etc) pretty quick, whereas the USSR ammo depots they had access to would contain considerable amounts of 100, 115 and 125 HE rounds, so a shift towards more HE rounds would make sense to me, at least."

Well, it is likely that those tanks did not serve in combat long enough for any ammo shortage issue to manifest itself. IIRC they were taken out relatively early during the fights. However barrel fired ATGMs were a limited issue and several models required advanced training to be used, so I think that removing them may make sense.