For the price, because the benefit will be totaled to purchase all supplies only one owner, including the consistency of the quality of the product.In order to spread the risk from the lack of delivery of goods.
The interest rates Due to consolidate all orders for supplies only one. The consistency of the quality of the product itself , to spread the risk of lack of delivery.
For the sake of the price Because it can be totaled all orders to suppliers only. The quality of the uniformity of product.To spread the risk of lack of goods.