Sharing Violation

[Scott Phelps]

I have a user using Excel.  When they save a new spreadsheet permissions
are 700, However, when they try to re-save the same file they get a
Sharing Violation and the file permissions get changed to 070!  What
gives?

Heres the config:
[homes]
   comment = Home Directories
   path = /homes/%u
   force create mode = 700
   force directory mode = 700
   browseable = no
   writable = yes