this the concept of premium tatkal, i think this would apply to premium trains too, but not sure kindly confirm the same from some one
"After booking of the first 50% of tatkal tickets under tatkal quota, the subsequent 50% tatkal tickets will be sold on dynamic pricing. The fare shall increase by 20% after each slab of 10% berths are sold subject to the existing cap (maximum fare chargeable) on dynamic fare"