I noticed that when I use the enter all after 12 a.m. HP time (9 p.m. my time) it enter's my horses into that day's shows. 

So when I try to enter them manually it'll say "This show has already run." Which makes sense because on HP time it would be the same day (my time it would be tomorrow so sometimes I forget to change the date, which is how I noticed this.)

Even though it seems the shows have already run (or should've because horse shows run at 12 a.m., right?) the horse's energy for that day is still deducted...although I'm not sure if it's getting points? I guess I could look...

...I hope I'm being clear O__O

Hmm. If it's entering the shows it's probably still getting the points, but you may want to double check that! I can also try to test it tonight. My THOUGHT is that the shows stop being able to be entered at midnight by the game, but they don't actually run right at midnight, so what I'm wondering is if there's just a lapse in the code for enter-alls and it's still letting you enter? Does that make sense?

Also, is this horses or dogs or both?

Yes, that makes sense. I was only training horses at the time (this account: http://horsephenomena.com/home.php?id=32679). I tried to see if the horses got points (I was entering them into shows running on 6/2) but I'm not sure since those shows have definitely already run.

you can back train with an enter all up until 1am hp time for horses
usually its 1215-1230 with dogs to back train (if you are lucky)