Does the weight have to be equal on each side of the dumbbell?

BowFlex® SelectTech® Dumbbells provides the unique option of offset weight selection. Offset weight selection involves using a different weight setting on one side of the dumbbell relative to the other, assisting in supination and pronation of the wrist and forearm. During offset weight selection, the combination of weight plates selected will not be the same on both sides of the dumbbell, so it must be returned to the base in the same orientation that it was removed.