Yeah I got a peak at CD 20 and 21, first time using the CBFM. I didn't trust it completely though and used cheapy OPK's too, specialy when I was getting high readings because I was afraid of missing the O. I also was going to use the OPK's after the 20 sticks if I wouldn't get a peak.
I did a chart search on FF and searched "all" (not just pregnancy) "late ovulation" and "using CBFM" and got some with as many as 12 highs and then a peak.
Good luck Avistar

I'm sure you're just O'ing late.