Maybe. But reflexing both ailerons puts them both in the relatively inefficient TE up condition; usually we see a less effective roll control in the up direction (until the wing stalls due to flap effects, but that's usually outside normal aileron parameters). I'd say you probably get better aileron effectiveness by slightly drooping the ailerons, putting both on the 'good' side of neutral.
But I'd say it would be quite a minor effect in most cases, unless you had control system tension issues and needed to preload the cables....maybe.