https://developers.weixin.qq.com/miniprogram/dev/platform-capabilities/business-capabilities/order-shipping/order-shipping.htmlhttps://developers.weixin.qq.com/miniprogram/dev/platform-capabilities/business-capabilities/order-shipping/order-shipping.htmlhttps://developers.weixin.qq.com/miniprogram/dev/platform-capabilities/business-capabilities/order-shipping/order-shipping.html

子单中有其单独的order_key结构，所以在外层的order_key应该怎么填

1. 假设我有额外邮费，例如12元，我是否应该在外层order_key中填入，子单中是否需要填入同样的结构？
2. 假设有多件包邮，邮费为0，0元单无法在发货管理中上传，这样怎么处理？