Appointment based tracking and not time based

The time based tracking gives the incorrect indication of the clients progress when hovering above it. The client may have had three appointments in total and missed two weeks of care so the care plan would then indicate the person is actually two weeks ahead of care. E.g cate plan of 2 x week 4 weeks then 1 x week for 4 weeks. Ther person comes for two weeks then has two weeks off. At that point the schedule would show the person needs to come 1 x week 4 weeks because it is time based yet they have actually missed two weeks of care.