Time format in Excel using excel4node

I am trying to print the number of hours in excel sheet using excel4node application. although the number of hours is getting printed in the excel, I am not able to get the sum or average while selecting that column.

Its only counting the columns not calculating the sum of the hours.

I am expecting the average while selecting the columns (Marked in RED color)

But what I am actually getting is counting of columns(Marked in RED color)

 ws.cell(i+2,j+2).string(value).style(bodystyle);

value here contains the number of hours.

Ask me for more Clarification.