Using GPO to disable Macros on Office files except from File Servers

Hello,

I am trying to disable macros from running in Office programs using group policy.  I have a policy set up with the following settings:

Policies/Administrative Templates/Microsoft Excel 2013/Excel Options/Security/Trust Center/VBA Macro notification Settings: Enabled: Disable all except digitally signed macros
(This is also set for Word 2013 and PowerPoint 2013.)
Policies/Administrative Templates/Microsoft Office 2013/Security Settings/Trust Center: Trusted Location #1:
Path: \\fileserver\
Date: 2016-03-24 (the date I created this policy to test)
Description: Any File on FILESERVER
Allow sub folders: enabled
(I have similar trusted locations set for all of our file servers.)

Based on what I read, it seems like this should disable all macros except for those from files on one of our file servers.  I tested this, and the macros on a shared Excel spreadsheet were blocked.  Now, this was a .xls file (not the newer format) - not sure if that makes any difference.  Please let me know what I'm missing here.  Thanks in advance for your help.