problem with nlapiGetLineItemValue

I'm trying to get the value of a changed line item on field change event and it shows the old value and not the new value.  Please advice.  I need to do other line item calculations based on the new value.  below is the code of fieldchange event.  On change of that value it triggers the fieldchange but my alert shows old value.

function fieldChanged_SO_CloseProcess_Main(type, name, linenum){
    var returnValue = true;
   if (name == 'custcol_mr_value'){
        var mrvalue = nlapiGetLineItemValue('item', 'custcol_mr_value',linenum)
        alert(mrvalue);
       
       
    }
   
    return returnValue;
}