Do logistic drones and vessels carry goods roundtrip?

Let's figure a transportation system where there are two Interstellar Logistic Station. Each one is demanding the other station good. When I'll put vessels in the towers, will they carry goods roundtrip? In other words, will they be assigned both for the "demand" and supply" requests?

Solution 1:

No. Each Logistics station (planetary and interstellar) operates entirely independently, and are not smart enough to perform "round trips".

No matter the origin or destination, drones are empty for half the journey.

In fact, it's even worse than that! Drones incoming from other logistics stations don't reserve their target resources! If you have an IPS with a hot commodity (silicon, say), and are also shipping it out via belts, it's entirely possible for the drone to be dispatched, arrive at the now-empty logistics station, and turn around carrying absolutely nothing!