Hotels will sometimes have 'House Accounts' reserved for promotional use - all the charges to that account are for promotional reasons, such as a complimentary cocktail for a certain rate type or a gratis meal for the booker of a large block of rooms.
Charging to a House Account is programmed in POS as a tender, or method of payment, not as a promotion. Therefore these charges will appear in your Payment Types reporting, not in your promotion reporting. If you wish to see these charges reflected in Promotions reporting, use a programmed POS promotion or discount button instead of charging to the house accounts.