[cflsystems]

Because your code assigns new value to $handling_special with each loop without adding the old one to the cart. You need to also include in the foreach code to add the value to cart if any then go to the next one. Something like

foreach ($int_hdl as $handling_special) {

$handling_special = field_value;
cart_total += $handling_special;

}
}


replace cart_total with the actual cart total field (or the field you are adding value to)