Qos Packet drops

Question

My question is : This subinterface has a Qos policy settings its speed to 800000 (800kbps)

If i have an offered rate of only 19000 bps, why is there a drop rate of drop rate 3000 bps ?

Service-policy output: MY_QOS_POLICY
    Class-map: class-default (match-any)  
      744825 packets, 268874044 bytes
      30 second offered rate 19000 bps, drop rate 3000 bps
      Match: any 
      Queueing
      queue limit 64 packets
      (queue depth/total drops/no-buffer drops) 0/0/0
      (pkts output/bytes output) 719286/245460560
      shape (average) cir 800000, bc 3200, be 3200
      target shape rate 800000

Answer 1

Note that the offered rate is a 30-second average. If your traffic is bursty then you may very well have had a very short burst of over 800000 bps (causing the shaper to kick in) and very little traffic the rest of the 30 seconds.