You are correct. First of all there is one big problem, it is easy to modify the chest (it is called compilatron chest) and get it working on a new map. However if I add 1 or more chests, it will delete items that players put near the chest in their save games.
The reason why Decu made the compilatron chest send resources overground is because he made it so that laboratories, rocket ships and power can only be created above ground (but you can also do it inside factorissimo2).
I think it's best to add a second chest, we do not know how other people set their maps. Most people usually build half their base above ground and half underground.
Also, I would want to make the chest bigger. 1x1 is too small, I was thinking 2x2 or 4x4