Saying that L maps take as long to play as XL maps is nonsense and absurd.
It's not just the size that matters, but also the structure.
There are no Gates of Order on 8mm6, so the first contact usually happens around week 2. Sometimes that's where it all ends.
Plus, road speed matters – Light allows you to set up the desired type of roads, so on 8mm6 there will only be fast roads. Given that good players' main events happen along the roads, this significantly reduces the duration of the game.
But on a CM map, with its poor road network and abundance of off-road runs, road speed doesn't significantly affect the duration of the game.