Hi Ron,
I’ve recently come across this issue and specifically on a managed WP hosting company that doesn’t yet recognize / support WP’s new built in capabilities. They are still recommending your plugin as the way to do multisite domain mappings.
Any chance you’re able to save a few headaches.. (even for many people using the plugin that don’t know why their dashboard takes an extra 10 second to load) by making a small patch and putting in a new minor release?