I think they meant that usually (90% of the time, say), you (know you) have a ~99.999% chance of getting your paycheck, and sometimes (the other 10%, say) you k

I think they meant that usually (90% of the time, say), you (know you) have a ~99.999% chance of getting your paycheck, and sometimes (the other 10%, say) you know you have <50% chance.