so do we just ignore the cost increase for teching ?
Quite frankly... Yes. It's included in the teching whether you use it or not. But if you use your infantry they will become complete as you play. You can't quantify how much of the tech is allocated to each bit. Even right now, bp1 gives lmg, rifle nade and panzer grens. As well as part access to a new tier. How do you decide how much is split into each? How much of bp1 pays for panzergren access? Does any? Since it wasn't changed in price when they were MO Ed to t0? How much does the RG cost of that battle phase? Nobody knows because it's not disclosed. Or more likely it doesn't have a value. I doubt that if for some reason the rifle nade was removed that tech cost would change at all. It's a bonus that is timed behind teching rather than an ability that costs like teching. If that makes sense....
The fact of the matter is we CAN quantify the conscript upgrades because they do nothing but things for cons. The price of the upgrade is a direct increase on the cost of conscripts as they only benifit them.
Most other sidegrades effect multiple squads in the core army, like weapon racks, or bolster (brit grenade tech being an outlier, meaning YES getting grenades on Tommies increased the amount paid per squad indirectly, since it has no other value elsewhere)