We went to the trouble of using Shopify's order number prefix so we could match our ecommerce orders with order numbers in our ERP software. This allows our shipping invoice audit team to easily match Fedex bills with their respective orders. As a company we ship hundreds of shipments every day and not only does SE not download the full order number correctly, but the workaround "Alternate Order Number" is useless because it is not an option for the Fedex reference fields. Other softwares have many more options for the Fedex and UPS reference fields so I know it is doable. Please download the Shopify orders correctly and also increase the options for Fedex reference field population.