Validate Line problem

I'm trying to compute/recompute values from a variable number of sublist items after lines are added or edited for a new SO.  While I can use the nlapiGetCurrentLineItemValue to correctly access the most-recently selected line, I'm unable to access the other lines using nlapiSelectLineItem. 

function updateWatts () {        var line = nlapiGetCurrentLineItemIndex('item');  // current 'item' line   var numLines = nlapiGetLineItemCount('item');  // line count = 0 for first line as line not yet committed at script trigger time   if (line > numLines) {     numLines = line;    }   var computedTotalPanels = 0;   var computedTotalWatts = 0;     for (var i = 1; i <= numLines; i++) {     //nlapiSelectLineItem('item', i); // ERROR:  when this line used AND a second 'item' defined, control returns to function start resulting in endless loop ("InternalError too much recursion")      var stringPanelQuantity = nlapiGetCurrentLineItemValue('item', 'quantity');      var panelQuantity = parseFloat(stringPanelQuantity);     var panelRate = nlapiGetCurrentLineItemValue('item', 'rate');