Change column subtotal from average to sum

Hi. I just can't figure it out how to make one thing that looks pritty simple, but I still find it difficult to understand. 
Column values "Evening", "Morning", "Night" are averages because I have set it up in the values field. Screen attached:

Also the "Total" column is showing me the average result. But is there any possibility to change it to sum function where it would sum the "Evening", "Morning" and "Night" columns?  Or maybe there is some kind of formula, that could do it for me in the data table? Here is the screen shot of the table:

Basically I need to understand how many  workers worked totally in one day, week or month, just sum up workers of all shifts that day. 

Thank You in advance.