It is not a rate code. It is internal code to show that the guest made an Advance Purchase (AP), have breakfast includsive (BKF=Breakfast) and have a credit card on file to guarantee (GSTCC= Guest Credit Card). TPI probably means the booking channel is through Internet and a direct booking, or possible the traveller type is international rather than domestic. 00p probably means the guest has no guest history in this hotel, or no membership with IHG, or be a lowly Platinum member of IHG.