Now see I do it a little different because I offer more than 1 option and use calculated shipping. I just check the free shipping square next to the shipping services. I use first class USPS and check the square then I add Priority. So it shows up with free first class and a not free priority-
I also use it for Parcel Post free and Priority not free- Of course I put the weight in the calculated option.
Hope that helps someone!!
Annette