Missing Orbits on the System Worksheet?

[archhealer]

Erm... I searched the old posts, but couldn't find anything. Is there a reason orbits 20 and 0 were removed from the T20 system worksheet? Especially since according to the THB, orbit 0 is the only habitable zone for a Red Dward, the most common star BY FAR in this creation system?

 

[far-trader]

Orbit 20 doesn't exist because the roll is 1d20-1.

I have no idea why orbit 0 was left off