Algol Plus Ltd

add_filter( "wpo_get_customer_by_array_data", "wpo_show_customer_phone_number", 5 );
add_filter( "wpo_after_update_customer", "wpo_show_customer_phone_number", 5 );
function wpo_show_customer_phone_number($data){
  if($data["billing_phone"])
    $data['formatted_billing_address'] .= "<br><b>Phone:</b>" . $data["billing_phone"];
  return $data;
}