I dont think cancellations only 450 berths approx are allocated for booking first and WL allowed out of 800 berths later the middle berths are adjusted and due to cancellations of some stops the the difference in GN WL and current WL is so huge. Check the availability on 29 june to july 7 tou can see further 150 berths are allotted to tatkal from july on 300 in General quota. I am saying this as it was written ineenafu that 1496 bookings 1276 boarded and the same say Falaknuma 1500 odd travellers travelled on that day.