The first time GTP is activated it stores the licence ID and password in the Current User registry. When deactivated and reactivated the first key is the one that always populated even if a new one was entered. To update this you can Ctrl+F to find the key or browse to "HKEY_CURRENT_USER\Software\GTP Services\Revit Electrical" and update the key and password. Once this is done it will pull the new key on the next activation (does not require a restart of the application).