This Amex offer was on my Amex Business Platinum card. I used to use this card to ship fedex shipments. However, in the last year I have not, so it could be a targetted offer. Check your Amex account.
Since this offer is good in-store, you can combine this offer with $5 off $15 FedEx in-store coupon which is valid until 6/17 [fedex.com]
Get 25% back as a statement credit each time you use your enrolled Business Card to purchase Qualifying Services with FedEx Express & FedEx Ground. Delivery must be completed by 11/30/18. Limit $1,000 in total statement credits. See terms and exclusions.
Enrollment limited. Must first add offer to Card and then use same Card to redeem. Only U.S.-issued American Express® Business Cards are eligible to enroll. Your enrollment of an eligible American Express Card for this offer extends only to that Card. Limit of $1,000 in total statement credits per American Express® Card Member. Valid in-store and online. Offer valid on purchases on the following Qualifying Services: FedEx Priority Overnight®, FedEx Standard Overnight®, FedEx 2Day®, FedEx 2Day® A.M., FedEx Express Saver®, FedEx 1Day® Freight, FedEx 2Day® Freight, FedEx 3Day® Freight, FedEx International Priority®, FedEx International Economy®, FedEx International Priority® Freight, FedEx International Economy® Freight, FedEx Ground, FedEx International Ground®, FedEx Home Delivery®, shipping transactions made via FedEx Ship Manager/FedEx Ship Manager Lite, and shipping through FedEx Compatible Solutions. Excludes invoiced shipments, international duties and taxes, other brands (Custom Critical, Freight, TechConnect, FedEx Office, Trade Networks, CrossBorder, Authorized Ship centers), FedEx SameDay Delivery, FedEx Delivery Manager, and Cold shipping solutions. Offer is non-transferable. Statement credit will appear on your billing statement within 90 days after 11/30/18, provided that American Express receives information from the merchant about your qualifying purchase. Note that American Express may not receive information about your qualifying purchase from merchant until all items from your qualifying purchase have been provided/shipped by merchant. Statement credit may be reversed if qualifying purchase is returned/cancelled. If American Express does not receive information that identifies your transaction as qualifying for the offer, you will not receive the statement credit. For example, your transaction will not qualify if it is not made directly with the merchant. In addition, in most cases, you may not receive the statement credit if your transaction is made with an electronic wallet or through a third party or if the merchant uses a mobile or wireless card reader to process it. By adding an offer to a Card, you agree that American Express may send you communications about the offer.