estimate shipping add data to billing address as well

gistfile1.aw

/**
 * Initialize billing and shipping information
 */
public function estimatePostAction()
{
    $country    = (string) $this->getRequest()->getParam('country_id');
    $postcode   = (string) $this->getRequest()->getParam('estimate_postcode');
    $city       = (string) $this->getRequest()->getParam('estimate_city');
    $regionId   = (string) $this->getRequest()->getParam('region_id');
    $region     = (string) $this->getRequest()->getParam('region');

    $this->_getQuote()->getBillingAddress()
        ->setCountryId($country)
        ->setCity($city)
        ->setPostcode($postcode)
        ->setRegionId($regionId)
        ->setRegion($region);
    
    parent::estimatePostAction();
}