I think what is important to remember here is, that the Training Site is a help tool, it is also set up with known quantities as well as the supplied info. One thing it is not is perfect. There are a few contributing factors that throw some of the standard calculations off (elastic effect, trainer level, sub levels, etc)
I have a young trainee that took 3 weeks to pop (of full 48+) in OD, then he popped in 1 week, since then he popped at 2 weeks consistently until a few weeks ago and tonight on the 3rd week he popped again, hopefully he goes again next week.
It all works out, sometimes it is just disappointing.