I did an analysis on CREV where BTN opens and BB calls and board runs Kc7h2d 8c 9h and BTN cbets flop/turn/river for a standard size of 2/3 pot. BB flats preflop with 406 combos, or 34.5% of hands (88-22,ATo-A2o,KJo-K6o,QJo-Q8o,JTo-J8o,T9o-T8o,98o,A8s-A5s,K9s-K5s,Q9s-Q5s,J9s-J6s,J4s-J2s,T9s,T6s,98s,87s,76s,65s).

BB defends 51% on the flop and then meets the minimum defense frequency on the turn, calling with 59.5%.

When BB checks to BTN on the river, I get to the conclusion that betting anything less than K9 for value would be a mistake when I compare both options by setting a 50% weight to betting. In fact, K9 is indifferent between the 2 options if we don't call a c/r shove with it from a balanced range of sets/65s/bluffs. If we call the c/r with K9, then we do better when checking.

Those results really surprise me but I was wondering if that is standard or not. There is a chance I made some mistake, as I'm not using CREV regularly, even if I verified my ranges afterwards. I get that we should cbet a tighter range on the river when villain slowplays all his nuts on earlier streets.

Is the BB's calling range too tight? Anything else I'm missing?