Hi,
The original topic was closed to I’m posting this here. I was able to resolve my issue. After rounds of uninstalling and reinstalling the client and avc pack and experimenting with the configuration option I discovered that enabling and configuring the “Use a specific display encoding” under the Performance tab in the Server preferences to H.264, even with the AVC pack installed correctly, it seemed to be ignored and the connection would revert to VP8. Leaving this setting unconfigured as default, the AVC pack works as expected and the connections are encoded in H.264. I am not sure if this a bug or by design or what.
I hope this helps someone else that may be having this issue. Since the original post I have updated to the 6.x release and the behavior is as described above.