Conditional Formating-The spreadsheet is for our backup logs success fail

Hi Guys

The problem i am having is on conditional formatting in excel 2007. The spreadsheet is for our backup logs success fail ect.

Our clients rent certain space on our server. The problem is i have setup conditional formatting to colour the cells in question a colour when they go over there allotted amount. On some clients it works fine but on others the can only be using 2.03GB of there allotted say 15GB and it flags up in the colour advising that its over there amount.

I cannot work out why i have deleted the rule recreated it i have saved it in many formats please see attached spreadsheet for example.

Cheers James