Late charges program not working correctly

Dear Team,

We are using the Late Charges functionality. Following are the setups which are set at Customer level under Late Charges Tab for all the customers:-

1) Late Charges flag enabled

2) Credit Items check box is enabled

3) Overdue Invoices Only enabled

4) Interest Calculation Formula, Rate and Type are set

5) Minimum Customer Balance Overdue is set to 666

But few Customer which are having balance less than Minimum Customer Balance Overdue (even for negative balance also) still Late Charges got generated. But it is not happening for all the customer.

So my question is that whether the 'Minimum Customer Balance Overdue' once set then if the Customer balance exceed that balance then only late charges will get generate. Else there any other set of setups also which Late Charges program check along with this setup.