Ships Type 7 vs Type 8 dimensions vs landing pads

[CMDR Jasper Lit]

I had been told that the type 7 was a large ship because of its height, but upon checking out the dimensions of the type 8 it is actually taller and bigger in every dimension than the type 7, but it is a medium? Why?

 

[PilotB]

The type 7 is a brick up to it's max height. The type 8 hull is quite slim with engines that retract when docked to let it fit.