At the beginning of coh2, in beta, there was a time when pgrens had single shreck for 60 muni. It was really OP as it came really early that way, was enough to fend off light vehicles, didn't hurt AI too much and was ideal for blob composition. Really the same problems as volk blobs but cheaper and earlier.
To solve the problem it was decided to replace it with double shreck upgrade. That way it came way later and made the unit useless against infantry with upgrade - as it is right now. It also was impossible to use other ostheer muni goodies at the same time as shreck early game - flame ht, lmgs, mines and so on.
This is why they gave it higher cost when they introduced shreck on volks - they knew it is going to be OP but thought it will be too expensive to blob. Truth was, that this time the unit itself was way less expensive so people used muni only on shreck but still managed to blob them really hard. This is why it was fixed by moving to more expensive unit. But giving it price reduction would mean we are going the same, bad way for the third time.
Your tale is BS.
Anyway give sp's double shreks for 120.