EPM does not use extension settings for Sangoma phone codec settings

For years, all my phones have been on-LAN and used uLaw. Now I have remote sites to add which are on MPLS, so no NAT, but have slow T1 connections. I'm looking to change the codecs that they use. I'm testing iLBC, OPUS and G.729.

When I Disallow ALL codecs and Allow only the testing codecs for an individual extension, I see that EPM rebuilds the config file of the Sangoma phone associated with that extension. However, the extension-specific changes are not there. The config file contains the global codec settings from the Asterisk SIP Settings module.