Credits not merging due to pricing tier limitations

Customer reports that credits are not merging into a single item. This occurs because the credits originate from different services, a setup necessitated by varying pricing tiers and associated credit amounts. The current system does not support different credit amounts for different pricing tiers within the same service. The customer suggests implementing a feature to link credit types to services/add-ons or to allow individual credits per pricing strategy. Admin acknowledges the suggestion's merit and will investigate feasibility.