The difference can be checked by running a specific report at the period you are looking at, the steps are below:
From the Access Legal Fusion Accounts Desktop go to the Reports tab.
Select Report Generator.
Select the Folder called Debtor Bill Checks.
Highlight the report called Unpaid Bills Check.
Select Run Report.
Select OK and then put the Year in click OK again.
Put in the Period.
Select OK.
This should tell you the files that have a difference on and then these can be rectified.