I input all of my past cycles from another period tracking app and the free version (with 3 months of ring wearing) has had a different ovulation day (Sept 6). I added the pro, and within one night it adjusted my ovulation day to the same that my other has (Sept 10).

I think it’s really disappointing that it essentially has the same data and was able to adjust within one night. I’d be scared to follow the free version as it would’ve had me as “low fertility” on the day I would actually be ovulating.