The hours are inclusive
From 9 to 17 means any time from 09:00 up to and including 17:59, which is what people mean by "between nine and five" even though it is not what it says.
Set the later hour before the earlier one and the range wraps over midnight, so 22 to 4 draws from the small hours as well.
Rounding narrows the draw
Rounding to the half hour over a nine-hour span leaves eighteen possible answers rather than five hundred and forty. That is usually what you want for a meeting and rarely what you want for test data.
Nothing is sent anywhere and your clock is never read; the range is only what you typed.