Why would an octo gate change the amount of neutral area? A gate swap doesn't change the location of the microswitches or the size of the actuator.
The "area" remains the same, but proportionate to the rest of the space that the stick can move in, it is a larger percentage of the free space than in a square gate. Octo gate has less overall space because it cuts off parts of the corners, meaning that the central area takes up more of the available space.