What is the problem that you are trying to solve? I see nothing wrong.
I'm trying to figure out what kind of digits i should write in, to have a composition e.x. 10 seconds long (250frames) . May be 12+02 ... or may be 33+17. hmmm.
There is NO option to write in normal way - 250 frames, or 00:00:10:00
There is always this stupid "+ sign"
Actually, this situation happens when you try to use this "new supersettings by Adobe called "Sync Settings"". It doesn't work at all - it just resets your settings with no way to turn back saved ones. If You press Sync, and Cancel the first dialog after them, you'll get this crap. And there is no way to fix it, except just "Syncing Settings" ... i mean - resetting them, because Syncing is not working service.
Change the project's time display settings from feet + frames to time code. Or do you change it in the comp settings? I'm not at my AE machine at the moment, and I forget. But it's in one of those two places.
Your time indicator is set to read feet and frames for film. Hold down the alt/option key (if that doesn't work they control/command key) and click the time indicator to cycle through timecode, frames, feet and frames.
I sometimes get the shortcut confused and I'm not at a computer but if one doesn't work the other will. You can also change in the composition settings.
hmmmm.mmja ... what can i say.
i'm with After Effects since version 3.0 in 1997 or somethinglike that. Working with this software almost every day. Have never checked this box - i didn't know anything about feets+frames.