It was the XPath you'd used - it was absolute instead of relative:
/dfs:myFields/dfs:dataFields/my:SharePointListItem_RW[1]/my:Project
The above will always get the first item. From the field you were on (Project)
../preceding-sibling::my:SharePointListItem_RW[1]/my:Project
will get you the one above.
I've attached your form with this change.