By my quick calculations... on 9.5x the distance between the thick post on a 30/30 ret and the crosshairs at 45 yards is 72mm which is 1.7 milldots, not 1 mildot.
Perhaps you don't have a standard 30/30 ret ?
Although from your holdovers, that sounds about right to me...
If I'm zeroed at 35 yards, 45 yards is about 0.8md (I normally use top of first dot down as my aimpoint).
If your 30/30 ret is correctly calibrated and you're aiming halfway down the thin post, that should be (by my calculations) 0.85md which is the same as my holdover... but it's not 1/2 a md it's almost 1 md.
I'm not saying you can't use a 30/30 ret for HFT, not at all.
But personally and I'd say for the vast majority of other shooters out there, expressing aimpoints in terms of md is much easier and gives much greater accuracy than guessing half and quarter distances on a 30/30 ret.
So as an example, on a rig zeroed at 35 yards with a half mil ret. 40 yards is going to be almost exactly on the 1/2 md mark.. which gives you a very definite aimpoint and 45 yards is going to be top of first dot down. Again it gives you a very definite aimpoint.
When you're designing a scope to sell, you need to cater for the largest market, and that I'm afraid at the moment is multi-aimpoint rets - usually with half mildot increments.
But HFT is still a tiny market.. so any 'HFT' scopes would also need to appeal to all the other markets out there to make it financially viable. Other markets do want to use more than 1md of holdover, so you'd need to cater for those shooters too if you wanted to shift more than a dozen or so scopes.