Confused and quite upset

I've been using this app for quite some time now and following my fertile days through here and another app. Out of curiosity I went to the ept (the preg test) website and it's calculating my fertile days a week after glow is!

The last day that glow is counting as my fertility window is showing as the first day and beginning of my fertile week on ept.

Not sure what to think but I would trust ept more if you ask me. I'll just be upset if this has been calculating everything wrong...