Geting wrong position of row (fnGetPosition) after adding a new row by fnAddData

sayedfarhan1

I have added an new row dynamically to a datatable as below

var otable = $('#sort_table').dataTable();
otable.fnAddData(["col1","col2","col3"], false);

$('#sort_table').each(function () {
dt = $(this).dataTable();
dt.fnDraw();
})
first row has index number 0 but after adding a new row in datatable index number of previously added row is same.

Is there any way to set index number of row?