I don't have the rulebook to hand, but it sounds like the magnitude step that happens at level five is causing this. Up to level 5, adding one magnitude adds one level, not five. So a Base 2 spell at Touch, Momentary, Individual is level 3 (Base 2 +1 for touch). A Base 5 spell at Touch, Momentary, Individual is level 10 (Base 5 +1 for touch).
I think that it's worth mentioning that might doesn't come in magnitudes only spells do. The construction "of a might equal to the level of a spell of base level + 2 magnitudes" is sufficiently clunky that despite its accuracy it would prompt more questions than it answered.
The guidelines are after all just guidelines, the weirdness that comes about when the DeO spell guideline is taken below level 5 might reasonably be ignored by anyone who isn't thinking that the guidelines are hard and fast rules.
Edit: upon rereading this post, I see that it comes across as far more arrogant than I intended it to. Please read it with a healthy quantity of "this is just my opinion" sprinkled on it.