Is there are better way to report Disk Space Used?

I like the resource “Top XX Volumes by Disk Space Used” for reporting on disk space. Most of the drives I monitor are in the 60 GB range so using the default filter of “VolumeType = 'Fixed Disk' AND VolumePercentUsed >= 90” works fine but there is the odd 100 GB drive and when it reaches 90% I still have 10 GB free (which I don’t want to see it on my dashboard yet)

I’m trying to think of the best way to cover this scenario and I’ve come up with this but I wanted to know if there is there a better way and I'll just have to keep adding more OR statement to cover larger and larger drives?

VolumeType = 'Fixed Disk' AND VolumeSize >= 100000000000 AND VolumePercentUsed >= 95 OR VolumeType = 'Fixed Disk' AND VolumeSize < 100000000000 AND VolumePercentUsed >= 90

Thanks,