addtotals would add all the field values, which I don't want.
I want the sum of the fields in such a way that it only adds up the fw values, like traffic_infw1+traffic_outfw1, traffic_infw2+traffic_outw2, traffic_infw3+traffic_outfw3 and so on. Now, fw can change and so do their numbers.
So, if I have 10 fields initially, I should get 5 fields after the summation of required field values. and after that timechart would show 5 graphical lines.
Like in the screenshot shared in the question, I would want sum of field values of 1st and 5th field, 2nd and 6th, 3rd and 7th and 4th and 8th fields.