jQuery input updates all IDs, rather than just the one required

The issue I'm having is fairly hard for me to explain, but I have replicated it in a jsFiddle http://jsfiddle.net/6ms4T/1/

What I am trying to achieve is by updating the 'Quantity' text box, I want to display the value elsewhere (the line below which I'll refer to as the 'Cost line').

Basically, updating the first input box (qty_item_1) is updating all the (quant_) IDs in the 'Cost line', rather than just the one related to that product.

function recalc(){
 
 $("[id^=quant_]").text($("input[id^=qty_item_]").val());
 

etc...

Full code is here: http://jsfiddle.net/6ms4T/1/

Any help would be appreciated.

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