Subway has footlong and 6-inch. They are clearly stating the length and it is unambiguous.
Selling 11” and 5-1/2” instead of foot-long and 6 inch is clearly cheating the customers.
I've bought their product and I never felt cheated.
Scientists and engineers are taught about implicit precision.
There is a different expectation when buying a 1 foot long sandwich, a 1.0 foot long sandwich, and a 1.00 foot long sandwich. At 11.5 inches, Subway sandwiches meet the implied specification of being 1 foot long.
A 6.5 inch sandwich also meets the implied precision of "foot long", but then I would feel cheated.