When you are calculating 1-A in order to determine what portion of your range you must defend against a bet, do you reevaluate the calculation on every street? Or is it for your starting range for the whole hand? As an example, here's a hand I played where this came into question.

I open 77 from CO, BB 3-bets, I flat IP.

Flop: T83r, he bets 1/4 pot, I call. (Need to defend ~80%)

Turn: 8s, he bets 2/3 pot, I call. (Need to defend ~60%)

River: Qh, he jams for a pot-sized bet. Hero? (Need to defend ~50%)

So in other words, since my calling range becomes progressively winnowed down (eg. I lose bottom 20% of my range on the flop), I am calling turn with the remaining 60% of my range, and calling river with the next remaining 50%, correct? (Which is to say, much less than 60% and 50% of my preflop 3-bet flatting range.)

Thanks!