This is really probably a daft question, but why would a numeric field with no decimal places in a SharePoint list (read from data connection) import into a form with many numerical places?
So this in the list : 4
Becomes this in InfoPath 2007 : 4.00000000000000
In infopath the field is simply a text field, which is fine as I'm concatenating it with other information.
Bizarre weirdness going on somewhere....