And have Luchs or Flak HT running around 10-20 fuel earlier? Such a change would upset the light vehicle timings way too much? It would also make all the tank rush strategies (using BG) worse, which would have a negative impact on teamgames where Mechanized isn't used as much unless people go for Stukas.
That way you could just move the flak HT to mechanized and stuka to Schwerer. It’s more of a change to tech routes in order to follow the Ostheer/Sov model, not so much the “both cheaper” part.
Point is if this was 2015 I’d just go for linear OKW tech instead of decisions. At this point this idea just can’t work.