True enough...
several of those services advertise that they are using there own imagery, and their own “quantitative yield calculations” in the the words of one service.

so they try to distance themselves from the USDA, whether they do or not in reality is another question. 

but I guess the bottom line is that if what a person is doing isn’t working for them, it's been my experience that wailing and the gnashing of teeth usually doesn't change a lot, gotta motivate yourself to do something different.