Word 2013 ignores the username setting in Options, but you can work around it. Add the following loop where indicated by the existing code:
Code:
If Val(Application.Version) > 14 Then
Dim oComment As Comment
For Each oComment In ActiveDocument.Comments
oComment.Author = Application.UserName
Next oComment
End If
Application.UserName = myUsername
Application.UserInitials = myUserinitials
Note that this will change the author for ALL comments. If there are some you wish to retain, you need to include code in the loop to omit them.