In the future, you could probably save some time and money by sending them to the lab yourself. The extension will no doubt send it to one of the UW soil labs:
http://uwlab.soils.wisc.edu/farm-soil/ The Food Plot test is a gimmick to make more money, and the field test is the same for nearly half the cost. A field test is $8 plus shipping.
Good luck with the tiller. It sounds like anything you can do to break up the soil will help.