I got this from Fujitsu support:
They also toldme:
We don't support the program, nor do we use it
We only support 3 APM settings on our drives
We have no idea what he will get if he uses any of the 127
values with this program.
Attached are the details of our 3 settings
beyond this I suggest he find out who wrote HDPARM and
ask them what the program is actually doing
i did not make any tests yet, but converting hex to dec i got:
FR = 05h : Enable APM = 5?
FR = 85h : Disable APM (Set Mode-0) = 133
SC = C0h - FEh : Mode-0 Active Idle Low Power Idle =SC = 192- 254
SC = 80h - BFh : Mode-1 Active Idle Low Power Idle (Default) = SC = 128 - 191
SC = 01h - 7Fh : Mode-2 Active Idle Low Power Idle Standby = SC = 1 - 127