+5 is either a snooze bar or, more likely, a "give me 5 more minutes of radio" when radio is in "Sleep" mode.
I don't know where the demand for "Sleep" mode came from-- suddenly both radios and TVs had timers that would turn themselves off. I, for one, would rather fall asleep outside of my bedroom than watch TV from bed, so I will never use it on TV. As for radio, well, I don't see the attraction, especially since the "put me to sleep" radio volume is far too far below the "wake my ass up" volume I'll need 7 hours later.