640/200/0 - schrecks are 100 muni per set on Pgrens, and you have to buy them as a set. Also, this assumes a vacuum where the AAHT isn't covered by rifles, which will eat schreck Pgrens since they have almost no AI (2x STGs) and are 4-model squads.
AAHT/Quad/Long-Range AI vehicles are exceedingly effective against T2-skip because of their range, which are less effective against normal T2 due to the Paks range.
One Pak is better than one Panzergrenadier squad against an AAHT.
One Pak is not better than two Panzergrenadier squads. Riflemen cover doesn't mean much when the double Shreck squads only need one volley to kill the AAHT outright.
If the Rifles get the advantage over the PGrens, the PGrens retreat. If the rifles get the advantage over the Pak, you lose the Pak to the enemy.
PGrens and Paks were balanced well against each other when they shared the same teching costs. Now that PGrens have a 200 MP 20 FU advantage, they win hands down almost every time.