It's early for me, but I think that as long as the stock is sufficiently stiff it is still against the bore line. I think you could have a stock that goes down 25" with a massive U shape and the u doesn't impact where the felt recoil is if it's stiff and not giving. The main issue with this design is you end up getting the recoil through the tab on the lower, but it seems strong enough.
Incorrect. The stock is attached to the action at a different point, few inches or so lower than the bore-line, introducing a little torque during the recoil. Flexibility aside.