I thought this would be simple UI task; the user can select an off-peak time for software updates to occur on their devices. This is for a IoT software deployment which may reboot the devices out in the field, taking them out of service for 10+ minutes.
Easy (pick a start time and install window length). This will work 90% of the time - most devices will apply the update during this slot & the process is done.
However for devices which are offline/busy during the install window, I need to allow an extra option; if the update does not occur during the slot ('tonight 2:00 to 4:00'), then allow a 'Retry' option. So try the installation again over the same time slot until it eventually applies or operator deals (via alerts/reporting) a terminal that is not updating.
Testing the dialog below with real users, had at least 2 users (out of 5 asked) completely misunderstand the dialog and how 'retry' works. I could fiddle with wording/explanation text, but wondering if I am missing something here? Is it really not obvious? I think if I have to add more explanation, then the UI is not self-explanatory enough.
There has been a few questions like this asked here, but most of them relate to setting up appointments in a calendar, so cannot find any applicable UI setting a precedent.