I have written several Excel VBA add-ins that are in beta and posted on our company's server for other colleagues to use/further develop.

A recent event has me confused as to how add-in installation and modification is managed, and what my best practices for development should be:

After I develop the add-in and install it on my machine, it lives at
C:\Users\nscott\AppData\Roaming\Microsoft\AddIns

To make it available to others, I copied it to a location on the server. I then directed the others to browse to that location in the Manage Excel Add-Ins dialog and install.
After installing, it shows up in that persons machine at C:\Users\*name*\AppData\Roaming\Microsoft\AddIns.

One colleague added some code so I directed him to copy the add-in from his machine back to the server with a date stamp. However, we discovered that his code was in the server version, NOT in his machine version!

How did that happen? I thought the installation process copied the add-in to your \Microsoft\AddIns folder, and any further editing would occur on the file in that folder, not on the file in the installation source location!

Thanks for any input.
Nathaniel