Client script to change sales order line item price levels

I'm struggling to build a simple client script that will change all price levels of items on a sales order to a level selected in a drop down box

The first item changes but then the script seems to stop at that point - so the first price level changes but doesn't commit and move to the next line

 function changeDiscountLevel()  {   var itemcount = nlapiGetLineItemCount('item');     //select the first line item   nlapiSelectLineItem('item',1);      //for the line item iteration   var i = 2;      do   {    //set the current item price level to the drop down selected value (dropdown is 'custbody2')    if(nlapiGetCurrentLineItemValue('item', 'price') != nlapiGetFieldValue('custbody2'))    {     nlapiSetCurrentLineItemValue('item', 'price',  nlapiGetFieldValue('custbody2'), false,true);     nlapiCommitLineItem('item');          i++;     //get the next line item       nlapiSelectLineItem('item',i);      }   }   while(i <= itemcount);  }  }