I have just updated my samba print server from 3.0.22 to 3.0.25c and I have discovered that my printing preferences, such as the default paper size being A4 are being lost, and instead the default paper size is Letter. Moreover, when I attempt to change it from the windows box, the setting changes locally, but only lasts for that session, and it is lost when the windows box is restarted, suggesting that no change is ever made on the server.
I finally worked out what was going on. At some point since 3.0.22, default devmode was turned on by default, printing defaults hadn't been set on some printers as I believed so when I upgraded they got the default devmode with Letter papersize. It seems the issue is therefore that a default devmode can't be replaced by a proper driver generated devmode so the papersize can't be changed.
I think this might have been me doing something stupid. Anyway, I am not seeing the problem any more.