$linetotal_cost = _round($lastcost * $item->qty / $item->marge_price_factor, 2);
$item->marge_total( $linetotal - $linetotal_cost);
$linetotal_cost = _round($lastcost * $item->qty / $item->marge_price_factor, 2);
$item->marge_total( $linetotal - $linetotal_cost);