Ghost 9 wont do increments

I have Ghost 9.0 running on 4 PCs with XP. Ghost is updated to latest
revision.

On one PC it will not do an increment, it only does a baseline backup each
time. I did read that if the drive changes enough it will do a
baseline....or a defrag...but that is not happening here.

On that same PC I tried this experiment, I did a baseline and just after it
was done did an incremental and it worked fine in that instance. But if I
let it do it automatically, once a day its always the large baseline back
and filename is baseline as well..

You know of some tweek or trick to get the incremental backsups to work?

Any tips appreciated