<p>We analyze the welfare effects of nonuniform pricing by a monopolistic platform that mediates between two sides of a market: There are symmetric buyers and asymmetric sellers, and one group of sellers imposes a greater cost burden on the platform. We demonstrate that the introduction of nonuniform prices on either or both sides of the market results in enhanced social welfare compared to uniform pricing on both sides. This improvement arises from the prevalence of cost-driven differential pricing over demand-based price discrimination. In contrast, when a platform is permitted to set differential prices on the buyer side alongside preexisting nonuniform prices on the seller side, the price discrimination logic may dominate on the buyer side. In such a case, whether welfare increases or decreases depends on a matching effect between sides, which influences the total number of interactions between buyers and sellers. These findings highlight the need for coordinated regulation, as the welfare effects of differential pricing on one side depend critically on pricing rules on the other.</p>