Hi Kevin,
Thank you for your very detailed response. We must think alike. I had followed your procedure almost exactly before asking for help. The good news is that it seems I may have found a solution today. I downloaded from Universal's website what appears to be a newer version of software than what I was initially using. With no changes to the configuration in software, a redownload using the new software seems to have resolved the problem. The range is back to normal now, even using the addressable mode. I had downloaded numerous times using the old software to two different remotes, and every time the same issue (with addressing on). Some day I need to revert to the old software and see if the problem returns. For now, all is well.

Thanks again,
Karen