I understand that the range would be +/- 2%, which would give us from 12% to 8% as a range, or 4% in total. I figured the 12% portion was inconsequential because once we're over 10%, the alarm should stop anyway.
That said, the disk space is NOT fluttering +/- 2%. It is saying fairly constant and we do get these alarms every 60 minutes without fail. I have tried rebooting the Monitor server as well, but this didn't help.
I saw somewhere else that there was a hotfix associated with reading available diskspace. It did not appear to apply to this particular instance, but I thought I would raise that point as well.