Well, that's probability for you. The reverse engineering odds are determined using massive sample sizes. As much as it doesn't feel like it, 22 attempts is not unbelievable for 1 out of 10 odds. If I did my math right, there's something close to a 10% chance of the results you got. While unlikely, it's not completely remarkable. If you were end up under 5%, most statisticians would probably say you're getting hosed. I think that happens around 29 attempts.
Then again, I'm not a statistician, I'm a law student. So it's more likely that I'm completely ignorant than I am correct. But there I go talking likelihood again...
((To check my math- (.9)^22 is .0985 = 9.8% odds of happening))