I recalculated the category using your proposed prices and we get a negative value for volume and sales
Out of the 85 items in the category you disagree with 58 of our proposed prices
It leaves me with 27 items and out of those 27 items 17 are prepriced : (big c / home brand / jumbo)
It is therefore not possible for me to gain the lost sales and volume since I have not enough item to play with to gain it back