In the current system of planet questing, you do not choose which item to put (say you have several instances of the different levels), and it either takes the first or the highest level or whatever.
The result is that if you have 2 instances at different levels or one that can be used on several planets VS one that can only be used on one planet, you cannot control which one is used and as far as I've seen it takes the "better" one.

I would suggest changing the algorithm such that the lowest level matching item, which is the most limited in use, will be the one taken.