Trever,
The Problem is in your system SAPOSCOL has stopped working. That's the reason in /sdf/mon the values visible to you are constant,
Please check the SAPOSCOL it will bw in hanged status.Check the Last write access Date/ Time and compare with the /sdf/mon constant values Date/Time. Sure you will get an answer.
Restart you SAPOSCOL, values in the /SDF/MON will again start recollecting.
Regards,
Prasad Jadhav