Could be, but I just tried it in the demo, did not work either. The 'Gross Total' field in SalesOrders is still there. Check the attachment to see what I did.
EDIT
It works, you need to completely remove the 'condition'. It doesn't work in my installation, which is a bit older. I have the Field Dependency map, but apparently there have been updates to that.
EDIT
It works, you need to completely remove the 'condition'. It doesn't work in my installation, which is a bit older. I have the Field Dependency map, but apparently there have been updates to that.