Appointments+ : Minimum times issue

Hello,

I have an issue with minimum times of appointments in Appointments+ plugin. I have set that appointments can be booked every 1 hour but my provider's schedules are different. Provider's 1 minimum time of appointments is set at 1 hour and half while providers 2 minimum time of appointments is set at 30 minutes. I have missed sth for sure but what is that? I attach an image to be more specific.

Thank You!