Last AF & EDD

Erika
Ladies the first day of my last period was January 29 & ended January 31. This app has my EDD at November 14, 2016 and says I'm 4 weeks but every other app says my EDD is November 4th and that I'm 5 weeks. According to my record I ovulated a bit after January 9th, which is when I got my positive OPK. Is your EDD & week off in this app?