Committing changes to JSGrid control without writing to underlying database

Question

I have a JSGrid Control which is being used to display timesheet data from an MS Project database. I want to add a "totals" row to the bottom each column of the grid which updates live on the client side and does not need to go back to the database.

I completed a preliminary implementation but I am running into a but that I cannot find the solution for due to the lack of documentation on the JSGrid. I am currently writing to the cell using the following method in the javascript:

       cell = GetRightPaneCell(records[records.length - 1].fieldRawDataMap.Key, fieldKey);
        //Update the total.  
        if (cell != null) {
            cell.innerText = totalHours;
        }

The GetRightPaneCell(recordKey,fieldKey) gets a particular cell and I then use to innerText attribute of the cell to write a total value (that I previously calculated).

The problem I am running into is encountered when:

    -I set the cell.innerText attribute
    -I scroll on the JSGrid such that the modified cell is no longer on the screen 
    -I scroll back to view the cell
    -The cell's value has been reset to the original value of the cell before I made the change.

I am trying to find if there a step I am missing where changes need to be "committed" somehow to the JSGridControl or if I am using the wrong method to change the value of the cell?

Thanks.