Servotronic steering gears

Hello.

I wonder why there is no more Servotronic (i.e. the steering gear) with A in the end in my Edgar (i.e. 4a1 422 065 A), but instead of 'A' 'AK' and 'AX', the AX variant is a whole 550 Euro cheaper than the AK.
For AX it is still under the part number "F >> 44-L-150 000*"

Can anyone tell me why they differ so much in price??

Thank you + greeting,
David