I did these tests to try to further understand the actual functioning of the AF Adjustment, and finally figured it out.
All lens swaps involved powering off the body. AF Adjustment values were checked in EXIF of the RAW pics.
Start with AF Adjustment Off, [ALL] = 0; [ONE]= unset
Power Up with 18-135 lens
Set 18-135 [ONE] to +2
Set [ALL] to +5
* take picture: AF used = +5
Swap in 70mm DA
Set [ONE] to +7
'OK' [ALL] at +5
* take picture AF used = +5
Swap in 18-135
* take picture: AF used = +5
Power Off/ON
* take picture: AF used = +5
Swap in 70mm
* take picture: AF used = +5
'OK' [ONE] at +6
* take picture: AF used = +6
Swap in 18-135
* take picture: AF used = +5
Power Up with 18-135
OK [ONE] at +2
* take picture: +2 used
Power Cycle
* take picture: +2 used
Swap in 70mm
* take picture: +6 used ([ONE] value I last set for 70mm above)
Swap in 18-135
* take picture: +2 used ([ONE] value I last OKd for this lens)
OK [ALL] at +5 with 18-135
* take picture: +5 used
Swap in 70mm
* take picture: +6 used ([ONE] value)
Swap in 18-135
* take picture: +5 used ([ALL] value last OK'd with this lens)
An [ALL] setting will over-ride a [ONE] setting for that lens IF [ALL] was OK'd last with that lens.
A [ONE] setting will be used for a specific lens IF that [ONE] setting was OK'd last with that lens.
SOO, as the manual hints, whatever value [ALL] or [ONE] was OK'd last with a specific lens will be the AF value used for that lens.
Sort of makes sense...as long as you are aware of it.