The MNSF for certain facilities is less than 1. Take Starports for example - I have heard from some people that the MNSF is 1 per 4 cities, and from some that it is .25 per city.
My question is: on a 1x1 asteroid, which can only have one city, will a starport make full income or only one quarter of it's full income? I think it would depend on if it is programmed to be .25 per city or 1 per 4 cities.
Doesn't MNSF go up based on the civ level of the planet? Since an asteroid is so much smaller, the civ level will go up that much faster, and might balance it out some.
As for the question, no idea. I assume that it only takes into account the number of cities, but that's based on nothing more than my own delusions. I do know that they make less on planets that don't have the required number of cities, though. (a cathedral on a planet with three cities makes less than one on a planet with six cities, for example)