Update ruined schedule

This app used to be so accurate. I have been using it for years and every month, its right on target. Since the update, however, its a mess. It allows almost a week more every time, so its always off by a week. I have so much data logged with this app, I hate to get rid of it, but its not accurate anymore. Can someone look into this, please?

TunedInTappedInTurnedOn about Period Tracker Deluxe, v9.5.1