There are two conditions that clutch adjustment is set to avoid: first is clutch is not dis-engaging when clutch pedal is pushed to the floor. On new cars or cars which have had a clutch rebuild, this is the most commonly encountered adjustment issue. On the other hand, in cars which have a worn clutch, adjusting so the clutch is not releasing too high with respect to pedal position. Also this second issue may mean the throw-out fork release-bearing is touching the pressure plate. This is checked by noting how much movement is at the throw-out lever or at the pedal ((1/2" as mentioned by your manual)
So really, if the clutch is disengaging somewhere in the zone between the floor and the at rest psition of the pedal and not at the extremes,... its OK.
The two figures the Haynes manual refers to are an overall guide for the operator to check the clutch condition and the actuating mechanism's condition. Provided the clutch is meeting the prior conditions above, I wouldnt be too concerned.
Jason