<?php
$this->reCalculateTotals();
?>

public function reCalculateTotals() {
    $this->getQuote()->collectTotals(true)->save();
    return $this->getQuote()->getShippingAddress()->getShippingMethod();
}

/**
 * Collect totals
 *
 * @param bool $force Should we ignore getTotalsCollectedFlag
 *
 * @return Mage_Sales_Model_Quote
 */
public function collectTotals($force = false)

/**
     * Protect double totals collection
     */
    if (!$force && $this->getTotalsCollectedFlag()) {
        return $this;
    }