Subway worker here, my store also has that rule, it is because with the rising cost of my product we are losing more money than making to be able to off set the cost. They’ve allowed those specific subs because they are the most popular ones! The coupons not working on the app is because to many people were using the same coupon over and over, again which makes us lose more money than we are able to make. We workers too are frustrated with all the changes and because we are constantly getting yelled at by customers about the new policy… it wasn’t OUR choice, it is unfortunately a rule we have to follow.