5 nites RFB and 4 at hotel rate but to be evaluated for comps at end of stay

So the action given during the RFB time does that count only toward the last 4 nites OR is all play during the 9 nites applied to the RFB part and the rest?

I would presume all play would count. Perhaps you should ask the person who offered you this?

Try and get as much info up front. Ask them what level of play would cover the last four days. If slots, it should be coin-in per day. If table games it should be $x average bet for y hours per day.

Give the host the impression that you will be playing at these levels anyway, but just checking to be sure.

Once you get this info, make sure that same host will be on duty when you check out. If not, check with him/her the day before and see if the levels you have played are what was expected.

This can get a bit tricky, so talk to someone upfront.

I will do something similar. Play 2 days of casino games which are definitely comp worthy, then a discount rate for 2 or 3 days when I am playing poker , which would not be comped. Bellagio, Aria, Mirage,
completely understood and have been great. If I put in 8hours of play each of the first two days, they just comp the remaining days. If I only play 4hrs. per day, then I pay the discounted rate on the back end.
If I don't play at all, they will cut me off as a comped player. If I plan a trip to only play poker, I don't take a free room. I will do the discounted room rates and that is ok.

CET could not get their minds around this and have stopped any free room offers.
Venetian wanted me to make two separate reservations.
Wynn couldn't be bothered,( ok, I am not big enough for them)