Upgrades Plugin Usage

As noted in another thread, I just installed the Upgrades plugin for the first time. Everything seems to be working as it it should and it’s a great plugin!

However, I do have one basic question on it’s usage. I am under the impression that in addition to the ad_removal.php and quota.php files that I will be able to add any plugin that I want to offer as an upgraded service?

I was expecting that when configuring a “New Package”, the plugin dropdown list would list all of the plugins in my main plugins directory. This was wrong. Once I learned that only the plugins residing in the /mu-plugins/upgrade-plugins/ directory were the plugins that would show in the dropdowns when creating a package, I thought I understood. So, then I dropped a plugin in there (the Feedsmith plugin), and went back to create a package and I didn’t see it listed in the dropdown. So I tried a couple more with the same result.

Is this not the intended process?