Glow vs Fertility Friend vs Femometer

Hey guys!! I have three apps.. I mainly use Glow because I like the community aspect but I like fertility friend to log my BBTs.. I happened across Femometer and I downloaded because I liked the layout for the BBTs better than Fertility Friend and was considering switching from FF to Femometer.. well, all the apps have all the same information from when we started trying to conceive in July 2019 to present.. Glow and FF say that my period is due tomorrow and that I am 14 DPO but Femometer that has the same exact information says I am 12 DPO and that I’ll start in 12/10.. why do you think it would vary like that?? My luteal phase has generally been on point and 14 days (which would put AF to tomorrow).. any thoughts are welcomed but please don’t be rude 😊