Earliest Time in Event/Time Popover

***I should point out that our current production version is running 9.68. I'm in the process of bringing it up to date (i.e. version 9.80) but my question seems to be valid for either version. I've looked through the release notes and I haven't found any indication that this setting has changed.***
In the event popover, when you click on the time to select it, we want to be able to select what the earliest time will be. Currently (in 9.68) this seems to set to 7 am. I thought that the 'Earliest Time' setting would affect this but it doesn't. It only seems to affect the first hour displayed in the weekly or daily schedule views.
Is it possible to change the earliest (and latest) start times available in the time popover?
In the event popover, when you click on the time to select it, we want to be able to select what the earliest time will be. Currently (in 9.68) this seems to set to 7 am. I thought that the 'Earliest Time' setting would affect this but it doesn't. It only seems to affect the first hour displayed in the weekly or daily schedule views.
Is it possible to change the earliest (and latest) start times available in the time popover?