So you're finding that "The Galileo Seven" episode interior as seen, with headroom over Spock's six feet, and a machinery compartment under the floor, yields a bigger exterior than we can accept. That figures. They designed the exterior to be a vehicle you sit in, and then built the interior without regard for that. Also, the difference between 27.22992 and 27.23 is less than a 1000th of an inch. That is literally a coat of paint. So I'd go with some sensible rounding.