darkside1957 I am afraid that I cannot give you an answer since I do not know which promotion that you used. There are some few promotions that specifically exclude STPC in the promotion rules. It is those few that I am talking about. My impression is that it usually only applies to the very cheapest of cheap fares in which case the Directional ticket value as described in the Wiki may also come into play.
It should be stated somewhere in the e-mail confirmations you received on booking.