I get your point, but your example should have been "must be turned in by 23:59" or "must be turned in by 11:59 Friday evening". If you're going to use both, I

I get your point, but your example should have been "must be turned in by 23:59" or "must be turned in by 11:59 Friday evening". If you're going to use both, I might as well say "midnight Friday evening," or even the worse "12:00 Friday evening" as both of those are still straightforward.