Sum of column - Incorrect in table/matrix

Hi all,

 

Have a simple problem, can't seem to figure it out why it summing incorrectly. I want to just display the calculated measure in a table format ie pic #2 with correct sum.

 

MEASURE:   Cal Time per Event = SUM (Time per Event)

 

Correct when the "Time per Event" column is in table and not summarizing sum function.

 

 

BUT when I remove that column giving me incorrect sum. 

 

 

Then I tried to do quick summarize of sum of that column it give me matching that of  the measure.