A point-of-sale interface receives point-of-sale quantities for a number of individual items, as well as point-of-sale quantity for a miscellaneous group item that includes undifferentiated sales of one or more of the individual items. An item indexer calculates an item index for each individual item comprising a fraction of the miscellaneous group item sales attributable to the individual item. A sales disambiguator computes a revised point-of-sale quantity for each individual item using the item index and the point-of-sale quantities for the miscellaneous group item and the individual item.