Hi, make an export of your registry of these keys when you have the correct settings:
HKEY_LOCAL_MACHINE\Software\Microsoft\Office\Excel\Addins\
HKEY_LOCAL_MACHINE\software\Wow6432Node\microsoft\office\Excel\Addins

And after a log off/log on, verify that your settings is gone, and do another export of the keys and compare them

If these settings are located in the HKLM, you may deploy them with a GPO..