The odds on the core gameplay page seem to be misleading? That is, that's not what the odds actually are.
If you have a +2 or more on a skill test, the only way to fail is by rolling a 2 on 2d6. This seems to put the odds of that at 9.09%, but it's actually much smaller - there's only a 1 in 36 chance of getting snake eyes. 2.78%. Similarly, this is the chance of success on any roll where you need to get a 12.
Since all of the math seems to be in multiples of 9.09%, it looks like it was calculated as though all results, 2-12, were equally likely. But that's not the case for 2d6, there's a bell curve. A 7 has a 1/6 chance of being rolled, and a 12 has only a 1/36 chance. The differences are significant, and very much shift the odds around.