Different Fertile Windows

Jessica
Alright, my fertile windows changed with this morning's temps. Previously, Glow had me ovulating on CD15. I initially discarded my temperature on CD18 because our sleeping conditions were different. Discarding the temp, FF also had me ovulating on the 15th. Without discarding, it's on CD16. Glow didn't have my cover line or ovulation marker until today, and now I'm said to have ovulated on CD18. I am confused and frustrated.