Cisco Switching/Routing :: TR50 - Priority Queuing Of Packets On Frame Relay Subinterface

I need to get some low volume, interactive data, prioritized on frame relay PVCs across our network. I have followed the CBWFQ examples from cisco.com, but my test packets are still showing latency over 1 second. My lab set up has a corporate connected gateway router linked via FE to testrouter 50. TR51 has a T1 frame relay loop to another router acting as a frame relay switch. The other side of the FR switch has a 56k link to  testrouter51. I am sourcing test pings from my desktop PC, that are marked as AF43, and leave at a rate of 1/second, when the response comes back in time. I am using a Smartbits to generate some default class traffic at a rate of about 56Kbps only in the 'outbound' direction, toward TR51, as this emulates a file copy from corporate to remote sites, that is causing the AF43 traffic to suffer. Here is the relevant config on the TR50 device:
 
class-map match-all rtu-data
match ip dscp af43
!
policy-map frame-56
class rtu-data
    priority percent 20
class network-mgt-data
    bandwidth percent 5(code)