So I just tried rolling 2d20 (40 times) and these were my results:

5, 7, 9, 10, 10, 12, 13, 13, 14, 14, 15, 15, 16, 16, 17, 18, 20, 20, 21, 21, 21, 21, 21, 22, 22, 22, 23, 23, 25, 25, 25, 26, 26, 26, 28, 28, 29, 34, 37, 38

So if that means anything to anyone, there you have it. My playtest results.

Some notes: sometimes time can drag as you add up the results. D&D's d20 system doesn't have this problem.