Until ticketed, we only guarantee the booking class (being K) but not the trigger class. So, as inventory availability changes in the trigger classes, so too will the price point. We recommend that you ticket immediately, to secure the fare basis and price point.
If you need to delay ticketing, to seek approvals (as an example) we suggest you either;
Alert the customer (at the time of booking) so they are aware that the price may change
Book in NDC, where we have a 5-day price guarantee, regardless of inventory changes.