Um, Phil, not to nitpick, but if you have Magic Level 10 in anything and cast a level 1 req spell, you get 1/10th the fatigue, not 1/9th.
It's (according to everything you can get your hands on, including your own formula!
)
1/[(Your Level-Req Level)+1]
Or, in this case:
1/[(10-1)+1]
Or 0.1.
Just a point.
Wyatt