I usually surge on Day 15-16. My CBEFM gave me 3 bars on Sunday, Day 13. My husband was away for the weekend, returning Monday evening (day 14). Today I took the cbe advanced (smiley) test and got the solid smiley (yesterday it was a blinking smiley, Sunday it was a blank circle). I then proceeded to take 2 other types of ovulation tests. I believe they are also positive. I've been using my CBEFM for the 17-18 months I've been TTC. Thoughts? Obviously the monitor must have been wrong? FWIW, I took letrozole days 3-9.