They are two separate modifications working on different issues with steering disengagement.
The Cytron freewheel modification allows the motor to move freely once auto steer has been disengaged. It does this by utilizing the NC wire to toggle the nsleep function by de-soldering some components and adding a jumper wire. Without this you have to fight the motor to turn, or you have to manually decouple it from the steering wheel.
The ACS712 is a separate modification that allows the user to disengage auto steer by turning the steering wheel. The ACS712 measures the amperage sent to the steering motor, when you turn the steering wheel by hand with auto steer engaged it causes an amp spike that is more than the set point and auto steer disengages.
The ACS712 modification has little benefit unless the cytron is modified , or some other means of disconnecting the motor has been wired up.