Yes if you’re farming 50 acres of wheat there aren’t many acres to spread the costs over or dollars to be saved.   

That said, if he has auto steer he already has most of the cost sunk.  The cost to go to RTK vs the cost of the Rangepoint subscription is minimal.  

And again, you’re talking about yield.   There is money to be saved on inputs whether you believe there is or not.     Saving 4 bags of seed corn per year will pay for RTK and adding row clutches/section control to a 6, 8 or 12 row corn planter.    Saving 4 bags of corn really doesn’t take as many acres as you think it would, especially with odd shaped fields or terraces. That’s only ~10 acres of overlap.  

OP is in “South Central MN”, he’s almost certainly growing corn and beans as the primary crops.