Do you want to drain the potholes or level the whole farm to grade?   I-grade has built in function that allows you to survey an area and auto-generate a plane, to grade, with equal parts cut & fill w/o SWPro.   I haven't used it yet, but that's what the manual states. 

If you are going to be draining potholes then the SWPro+  would be of more value.  You can do a pretty good job of running the scraper manually off the screen if you are only cutting drainage channels.  I wouldn't want to be running it all day if I were trying to level the farm though.

SWPro+ is worth has a lot more value than SWPro................not sure why they even offer SWPro by itself, other than it allows them to charge more for SWPro+