I see, completely understand what you are saying.
Can you tell me what the difference of 'holes' is or why are they placed at certain points in the vehicle?
To me it sounds like the 2 round holes - based on the original location of the row of seats, are there for carrying people.
The slightly larger holes are a bit strange to me, why not also make these similar? at this moment, you can lock the couch in its place, but it is definitely not suitable for driving if you ask me? If you brake hard or accelare the couch can move.
Ofcourse there is a 3rd slot, but that's the slot to put the couch in or out I assume.
I should look if I got a manual delivered....