Shopify的运费率响应中货币属性的目的是什么？

Question

根据CarrierService API文档，运费率响应应包含货币属性：http://docs.shopify.com/api/carrierservice

下面的运费率示例响应仍会导致Shopify在结账时显示所有三个美元（或任何默认商店货币），没有转换，即相应地为12.95美元和29.34欧元和英镑。

{
  "rates" => [
    {
      'service_name' => 'Method A',
      'service_code' => 'RMG9A',
      'total_price' => '1295', # cents
      'currency' => 'EUR',
      'min_delivery_date' => '2013-07-13 14:48:45 -0400',
      'max_delivery_date' => '2013-07-13 14:48:45 -0400'
    },
    {
      'service_name' => 'Method B',
      'service_code' => 'RMG1P',
      'total_price' => '2934', # cents
      'currency' => 'GBP',
      'min_delivery_date' => '2013-07-13 14:48:45 -0400',
      'max_delivery_date' => '2013-07-13 14:48:45 -0400'
    },
    {
      'service_name' => 'Method C',
      'service_code' => 'RMG1D',
      'total_price' => '2934', # cents
      'currency' => 'USD',
      'min_delivery_date' => '2013-07-13 14:48:45 -0400',
      'max_delivery_date' => '2013-07-13 14:48:45 -0400'
    }
  ]
}