How to do total SUM?

In driver section A of my UBE, it has a level break footer on employee's number.  The sequence is set up using employee number. In this LBF, I want to sum up the employee's commissions.  I have the business view commission  field on section A and the LBF section.  I right click mouse on the commission field in the LBF and under the totaling tab, I checked the Total checkbox and selected Sum.

So let's say there are two records of employee 123456 and the commission field has 100 and 200 respectively.  The total should be 300.

But after I ran it, the commission field in the LBF contains some random number.