Why doesn’t the app update future predictions when I update my health data and settings?

When I first used the app a few years back, I set my data to say 28 days between the start of a period to the next. However now my body changed and there’s only 25 days between them.

When I go to my settings and change the days the pop-up says that this only updates past periods and doesn’t affect the upcoming dates on my calendar. But what’s the point then??

I need it to update the upcoming predictions because now it’s always incorrect for my cycle.

Thank you!