I appreciate this post immensely! I dont know if this helps to identify any additional issues, but local::lib can add confusion with this on top of use of multiple prefixes. Of course this means multiple module destinations, depending on "package" install or "manual" install. When I say "package" i mean stuff like apt, yum, rpm.. manual here refers to using cpan(p/m) and the like, which isn't what you would usually imagine.

Furthermore, I never came across an initial install sequence that would result in ::Smart being used instead of ::Simple (without the --plugin argument, or script editing directly).