Every woman's temps differ as to what "normal" pre & post o temps are. If you are temping correctly(immediately upon waking b4 getting out of bed)and you temps are running in the 98 range, I would say you have o'd. 98's are generally a post o temp.
Pre o temps can look like an earthquake on a Richter scale, lol. There's a lot of wacky things going on with estrogen during that time. After o, you should see a more consistant pattern as the progesterone takes over :)
It worked for me - kind of. I started using it last winter and got pregnant twice in the spring - both ended in miscarriages (they found in testing this summer I have a blood clotting isse that baby aspirin took care of) - a friend bought the VIP feature and she's 26 weeks or so... I'd agree with Tina - it uses the info it gives. Good luck! My temps were kind of all over the place so it was hard to tell when I was ovulating and such- I also used an OPK...
All i entered were temps. I can't say there was a real clear thermal shift. I had a lot of erratic temperatures. My most stable temperatures were between 97.9 and 97.7. Then my temperature went drastically down, up, then down again. Then it started going up.. 97.7, 98.1, 98, 98.2, 98.5. Does that sound like a thermal shift? sorry Im new to all of this.
FF is only as accurate as the info it is given. Something you entered told it you o'd on the 24th. Are you entering temps as well? Was there a clear thermal shift? If so, I would agree w/FF. OPKs aren't always reliable. Some women's surges aren't enough to trigger a pos result, too. If your temps show it, I would believe them over OPKs.