No, and I'll tell you why: Skills and spells have drastically different code.
In particular, drastically different fumble code.
As any merchant already knows, merchant skills fumble a hell of a lot more
often than warrior skills (which, in theory, are used more often). Spells, on
the other hand, have a generic "fumble chance" code that is based on many
factors, including cast XXX percent. It would be next to impossible to make
every skill fumble the same chance, nor would we want to, when some skills
have gentle fumbles (slash) and others are horrible, horrible ugliness (again,
ask any merchant).

Shinarae Lluminus