Dropping packets

I have a scenario of dropping packets in my class-default class under a specified policy-map (outbound) and I can't figure out why.  The priority and other defined classes don't get near their assigned "reservations".  I thought when that configured bandwidth went unused, it would be shared with the other classes.  The class-default in this situation is assigned 30% bandwidth and although it does spike above 30% sometimes, its not the norm.  Either way like I said the other classes are not being used to their limit so should be shared. Just makes no sense.

The physical interface is never compelely saturated per the show interface tx/rxloads either. 

Output:

Class-map: A-VOIP (match-all)
      213730 packets, 43472790 bytes
      5 minute offered rate 101000 bps, drop rate 0000 bps
      Match: access-group name VOICE
      Match: ip dscp ef (46)
      Priority: 40% (17684 kbps), burst bytes 442100, b/w exceed drops: 0

    Class-map: B-VIDEO (match-any)
      3328 packets, 2215861 bytes
      5 minute offered rate 2000 bps, drop rate 0000 bps
      Match: access-group name VIDEO
      Match: ip dscp cs4 (32)
      Queueing
      queue limit 64 packets
      (queue depth/total drops/no-buffer drops) 0/0/0
      (pkts output/bytes output) 3328/2215861
      bandwidth 25% (11052 kbps)

    Class-map: SMS (match-all)
      4 packets, 320 bytes
      5 minute offered rate 0000 bps, drop rate 0000 bps
      Match: access-group name SMS
      Queueing
      queue limit 64 packets
      (queue depth/total drops/no-buffer drops) 0/0/0
      (pkts output/bytes output) 4/320
      shape (peak) cir 1024000, bc 4096, be 4096
      target shape rate 2048000

    Class-map: class-default (match-any)
      12065683 packets, 4038396521 bytes
      5 minute offered rate 13498000 bps, drop rate 0000 bps
      Match: any
      Queueing
      queue limit 1024 packets
      (queue depth/total drops/no-buffer drops/flowdrops) 0/1446/0/0   (recently cleared)
      (pkts output/bytes output) 12063937/4037655219

      Fair-queue: per-flow queue limit 128 packets
      bandwidth 30% (13263 kbps)

policy-map WAN
 class A-VOIP
  priority percent 40
 class B-VIDEO
  bandwidth percent 25
 class SMS
  shape peak 1024000
 class class-default
  queue-limit 1024 packets
  fair-queue
  fair-queue queue-limit 128
  bandwidth percent 30

Serial interface:

bandwidth 44210

BW 44210 Kbit/sec, DLY 200 usec,
     reliability 255/255, txload 77/255, rxload 87/255