To find and use the invoice tolerance setting:
Click System, Options, Invoice Register Options
On the Tolerance tab, select the Invoice Register Tolerance check box.
Click Save. If you notice that the Tolerance tab is not being displayed, then this will be restricted because it is a chargeable option. You can always discuss with your Account Manager the options available.
To assign a tolerance to a supplier:
Go to Creditors, Suppliers and select the supplier required.
Edit the record.
Open the IR Approver window via the button on the ribbon.
Enter the Tolerance required
Close the IR Approver window
Save the record