The advancements do not track how much of an advance is spent on skills. So the only thing that I can think of is a mechanic that will look at the total number of advances on a lesser skill. After it totals it, it divides it in two and rounds down. This can possibly end up where a character will get a lesser skill and somehow spends a half an advance on something else (like a half-cost edge, or an edge that costs a half added to a base number, like 1.5).
However, there is a problem with this. I had initially figured that, since the character is using advances, the character would also want to use advances for the free skill point. This creates some circular logic. If you were to add skill points (as in character creation mode) that could work, but when you jump back and forth between a locked character and an unlocked character, if you have modified a skill through an advance it is locked, so the extra skill point would have to be applied to a skill that has not been modified through an advance -- ever -- or a new skill.
For reference, the advance for the Lesser Skill is "advBoost2".
Another idea might be to create a derived attribute for these extra skill points. Then make up your own version of "advBoost2" (it can be found in the thing_advance.dat file in the source folder). However, you cannot put a source on it so it would show up for everybody. Anyway, give that new version (advBoost3?) a 0 cost and instead use a mechanic to apply it against a derived attribute for these extra skill points.
Can you tell me the name of the edge and what book it is in? I might have the pdf and I can look at its description more closely.
