there's always going to be a symmetry issues, I have my right bicep bigger then the left, one calve is bigger than the other, there's nothing I can do about it, going higher reps on the other delt will not even it out, theres no proof out there that going higher on one specific muscle will even it out, try it for yourself go higher on the reps on that one side to see if it will help some, I could be wrong who knows, I'm telling u from my experience & it didn't work shit for me. Could it be how your are posing that makes u see one bigger than the other ? or is it really noticeable ?