Yes, I agree, if it ain't broke, don't fix it. If it rolls straight, it's good.
To explain the original answer to the question: Differential on non symetrical wings refers tomore up aileron movement than down aileron movement.Air flowing over the wing is "less dense" than air going below the wing. The ailerons are less effective in "lowerair pressure" regions, hence more aileron movement. Certain high wing, semi symetrical wingplanes like larger Cubs etc may need some differental to improve normal handling - like a tug plane, perhaps 20%.