Crystal Reports Cross Tab Question

Message

   Hi All,

Below is my cross tab in Report Footer Section,

                     Certification     # of Emp. Certified      # of Emp. Not Certified
Location A          Cert A                      10                              
                        Cert B                       8                               
Location B          Cert A                       5                               
                        Cert B                       4                               

Location A has 15 employees in total
Location B has 20 employees in total

How can I get the correct number of employees not certified? For example, there are 10 employees certified for Certification A in location A, and 5 are not.

I inserted a forumla ToText(DistinctCount(employee id, location) - CurrentFieldValue, 0) in the Display String. The number came out to be 10, not 5.

Thank you,