For those with the navigation system, the timers at first can be confusing and it is easy to make errors. Some screens require hitting an OK button, some just have a back button, and in the end the Save button is required for the changes to be finalized. There is no consistency on the timer screens. It is easy to forget to hit an OK button or Save button after making changes, and then the changes you thought were made are not saved. The timer could probably be simplified to one screen showing % charge desired, start time, end time, days of the week. No Save or OK buttons should be necessary. What you select and see is what you should get.