My assumption is that you for example have one gift for terminal level 3, 5, repair level 1 and 3, tower level 2 and 4. If you for example have ergonomic chair (which is needed for example for tower L4 and terminal level5), your one is for tower level 4, when you build your tower level 4 chair dissapear. (you still have gift to give for terminal level 5).Not entirely true, because I still need ergonomic chairs for my terminal. Guess I only had them in my gift and LA drops list until I completed the Baggage Hall. Is this possible?