OK... this makes perfect sense?!?!

The "old" pre-2011 models offered 1 mechanical hydraulic circuit and 2 electric-hydraulic circuits. Correct? The "new" 2011 models offer 1 electric-hydraulic circuit and 2 mechanical hydraulic circuits. Correct?
Not really, the 3rd is/was a regular spool valve made onto the loader valve-so all your are buying for $250 is the hardware to plumb it and the lever to operate it, the actual "valve" is already there.
The 4th and 5th can not be considered "electric-hydraulic" as you wrote, The "diverter" just directed the fluid from the loader lines to the rear couplers so you still used the same joystick to control them. So it's not really a EH circuit, just a front or rear control.
So, if you wanted a 3rd SCV on the old models: it would cost you around $200. If you wanted 4 or 5 SCVs it would cost you another $1,200 or so. Ok, $1,400 or so and things were good.
Well, not so good. With the $1200 diverter you did not gain two new independant circuits-you just "diverted" the front ones to the rear.
Now, if you want a 3rd SCV - it's around $900. And if you want #4 and #5 SCV it's gonna be another $1,200 or so. So, the end user has got 3 hyd circuits and it's now gonna cost around $2,200!!! And only 1 of those SCV's is an elec-hyd circuit?
I have not studied the new options completely yet, but user "bleedgreen" post this on the DT forum-he is a JD salesman:
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New and updated kits for 4320-4720 Compact Utility Tractors
EH third SCV on 4000 TWENTY Series Tractors
EH third SCV joystick for cab tractors
The new factory- or field-installed EH third SCV kit increases productivity by allowing improved loader applications such as a 4-in-1 bucket. The EH feature provides a smoother and quicker response to the operatorç—´ movement. The kit also includes a 12-V adapter.
Fourth and fifth SCVs on 4720 Open-Station Tractor
Fourth and fifth SCV controls
Fourth and fifth EH SCV switches
The fourth and fifth SCV kit provides two additional pair of rear SCVs. The kit can be field installed on a tractor with or without a loader. The functions are completely separate from the loader.
Updated power-beyond and electric diverter kits
The redesigned power-beyond and electric diverter kits provide a more reliable performance without affecting the fit or function.
New creep to reposition kit
This exclusive creep to reposition kit allows the operator to reposition the tractor and control the engine speed from the backhoe seat.
Compatibility
The new kits are not backward compatible. Please refer to the serial number break table.
Sorry the photos did not upload in the order I thought they would...
1)New EH 3rd SCV 2)New 4th&5th OS Controls 3)New 4th&5th Cab Controls 4)New 4th&5th SCV 5)New EH 3rd SCV Joystick
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So I am not sure how everything will work just yet.