Hey,

it recently came to my attention that many Regs seem to c/f 70% as PFA on the Flop(i play NL200 SH). 

So for example, we raise 3BB in MP and BU calls, blinds Fold. Flop is A72r and we check. BU bets 5 BB into 7.5 BB. So he is risking 5 BB to win 7.5 BB. B= 5/7.5 = 0.67. Thus, A = B/B+1= 0.4. So our minimal defense freq. should be (1-A)% = 60 %. 

Somehow i doubt we have to be defending 60% of our checks as PFA. So where is my error in reasoning?

Is it because we have a stronger Range than BU?

How should we construct a C/C range as PFA? Only include Bluffcatcher Hands? Or also Hands that can c/c all three streets comfortably. Problem is we always weaken our cbetting Range.