FWIW i had a similar experience with preferred leg changing through jumping practice. i'm a LR planter but left-footed for kicking anything and for as long as i can remember i was more comfortable SL jumping off my right leg than my left. those things shouldn't go together, especially since i'm right-handed so layups should be more natural off my left foot. at some point in the last year or so of the dunk quest that finally became the case, left foot SL jumps were at least as natural and high as right foot jumps. that's without practicing them especially, just lots and lots of planting and layups from both sides for warm up.
point is, chris is absolutely right that practice can groove new patterns and open up new possibilities.