You are correct that I was wrong. (I searched "fedex profit 2021" and incorrectly reported based on a quarter's profit, which is sloppy as hell on my part.)
That said, it seems like $75B is wildly too high as well. Page 43 of their most recent annual report shows a consolidated net income for the year ending May 31, 2021 as $5.2B, making $400M still a 7.5% boost (if it all passes through).
Wikipedia says their net profit for 2021 was $75 billion, so your math seems off.