In shorter format of game which is T-20 overs (the one you're betting), there are less chance of bowling team handing out 21 extras to batting team in single inning. I mean bowling team need to bowl really shit in that particular match to give away so many extras. But if its for full match then its completely possible that both teams could give away that much extra runs together.
* There are total 3 formats.
Tests (5 days, maximum 450 overs)
ODI (50 overs each team, total 100 overs)
T-20( 20 overs each team, total 40 overs)