I think there was a misunderstanding. I apologize. I had 22 listed as either unlocking from 20 or 21 because it wasn't clear since people had been sending ships to both sectors. I asked for confirmation, and someone said they confirmed it was 21, not 20. No proof was posted, but I took them at their word. I will change it to 20. If someone can confirm unlocking it from 21 via a trip that does not include 20 but does include the 22 unlock, I'll restore it and we'll have our first dual-unlock sector. Until then, I'm going to assume the person who "confirmed" that 21 unlocked 22 was in error since no screenshot was shown.