Where does the $12,000–$18,000 per month figure come from?

FSD (Supervised) for consumer vehicles currently runs $99 per month — Morgan Stanley rounds this to approximately $100 in their note.

A single autonomous Semi subscription would therefore generate roughly 120 to 180 times more monthly software revenue than one consumer FSD subscriber.

When does Morgan Stanley expect Tesla Semi to go fully autonomous?

According to the research, Morgan Stanley anticipates full self-driving capability for the Tesla Semi by 2027.