Not sure what's the point here? It's the nature of AP rates that you can't modify or cancel, and that naturally also applies when the price drops. You basically take a calculated risk. It's the same as when airfare drops.

​​​​​​Historically I always booked AP rates because I won more often than I lost. These days it's different, hotels seem to overestimate the demand and I've had too many occasions when the rates dropped shortly before the stay. I'm now booking semi-flex for most stays (unless the deal is really good) and then monitor rates for rebooking if they drop.