Flow Meter for W.A.S

My friend is putting a deere retro fit autosteer system into his 7410, when we were discussion how they are installing it (he is a deere mechanic and is doing the install) he said they are using a flow valve for the wheel angle sensor. has this been looked at in AOG? Im not sure of the cost but it would save the problem of Ackermann and the dance of mounting and positioning the w.a.s.
I will ask him if I can get the flow meter part number.

There is a picture of this here:

I think this would not work with AOG. The point of the WAS is for AOG to precisely know were the wheel are, especially when strait, so no need for fancy calculation or approximate steering. The JD system give the relative wheel angle change but (probably) no absolute angle. This need completely different calculations.