the results show a higher throughput in the second case compare to the first one.
Are these results right?
We consider that in the second case we should obtain a lower throughput because of higher interference.
The new version of the Vienna 5G Link Level Simulator is officially release since yesterday. I just tried this described setup with the new version and it behaves as expected: the throughput of both users decreases significantly due to the increased interference.
I highly encourage you to switch to the new version and start out with the multi-link scenario to simulate your desired setup.