[c-nsp] Drop and Queue counters mismatch

[MKS]

Hi list

I have c7600s with 6724 DFC cards.  Unfortunately I have a link where
i'm running into congestion (waiting on a second circuit). I'm using
QoS for important traffic, but there is a mismatch on the counters.

c7600#sh int g3/2
GigabitEthernet3/2 is up, line protocol is up (connected)
....
  Last clearing of "show interface" counters 01:06:41
  Input queue: 0/1024/0/0 (size/max/drops/flushes); Total output drops: 1107423


c7600#sh queueing int g3/2
Interface GigabitEthernet3/2 queueing strategy:  Weighted Round-Robin
  Port QoS is enabled
...
 Packets dropped on Transmit:

    queue     dropped  [cos-map]
    ---------------------------------------------
    1           554066  [0 ]
    2              382  [1 2 ]
    3                0  [3 4 6 7 ]
    4                0  [5 ]


Only half of the total output drops (1107423) is accounted for in the
queue statistics (554006+382).
Where can I assume that the unaccounted packets are being dropped?.
Should I assume that the packets are being dropped regardless of the
DSCP values or what?

Regards
MKS