A method of operating a charging system (20) comprises acts of defining a pool of plural asset accounts (24) and classifying the asset accounts of the account pool according to one or more account type classifications; and storing at least one appropriate account type classification for a product. The method further comprises, upon receiving an indication of a service request (6-1) involving the product, obtaining at least one appropriate account type classification for the product; and selecting from the pool of plural asset accounts (24) one or more of the asset accounts belonging to the at least one appropriate account type classification to charge (e.g., reserve/deduct) for the service request involving the product.