商家从中通了解到，长沙地区取号的中通物流单号是788开头。请求中所传的网店编码确实来自长沙，但是获取到的物流面单不是788开头的，请问这是为什么？

【POST】请求url:https://api.weixin.qq.com/channels/ec/logistics/ewaybill/biz/order/create?access_token=

请求数据:{"delivery_id":"ZTO","delivery_info":null,"ec_order_list":[{"ec_order_id":3725389840930183680,"goods_list":[{"good_count":1,"good_name":"葛根粉品鉴装","out_product_id":"6976915100","product_id":10000177163517,"sku_id":2918731125}]}],"ewaybill_acct_id":"663516****","ewaybill_order_id":"3814130922828218369","ext_info":null,"order_type":1,"receiver":{"address":"~湖南省 衡阳市 衡南县 ****~/shipinghaoxiaodian/~1~~","city":"衡阳市","county":"衡南县","mobile":"~159****7601~/shipinghaoxiaodian/~1~~","name":"~欧**~/shipinghaoxiaodian/~1~~","province":"湖南省","street":""},"remark":"","return_address":{"address":"","city":"","county":"","mobile":"","name":"","province":"","street":""},"sender":{"address":"葛掌柜微信小店","city":".","county":".","mobile":"13873116956","name":"童先生","province":"湖南省","street":""},"shop_id":"5009834516300","site_code":"73340","template_id":"6634854125"}

{"errcode":0,"errmsg":"ok","ewaybill_order_id":"3814130922828218369","waybill_id":"73615522662851","delivery_error_msg":"成功","print_info":"JTdCJTIycHJpbnREYXRhJTIyJTNBJTdCJTIyd2F5YmlsbElkJTIyJTNBJTIyNzM2MTU1MjI2NjI4NTElMjIlMkMlMjJwcmludFRpbWUlMjIlM0ElMjIyMDI1JTJGMDElMkYxNSUyMDE3JTNBMDklMjIlMkMlMjJzZXJ2aWNlcyUyMiUzQSU1QiU1RCUyQyUyMnJlY2VpdmVyTmFtZSUyMiUzQSUyMiVFNiVBQyVBNyoqJTIyJTJDJTIycmVjZWl2ZXJTI==","waybill_id_list":[]}