OK, just to simplify things, let's consider just one direction (vertical)
then to get new velocity program sums up accelerations (or decelarations) from 5 sources:
1. .up and .down. The values are directly related to speed, 10 .up means velocity will increase by 10
2. brownian motion. How are values from option screen relate to speed? What would 4 do, what would 8 do?
3. Friction. Same question - what do values in the option screen mean? Does it depend on bots' size?
4. Gravity. Same question.
5. Bouyancy. Is it 0 by default (meaning no effect)? Can it be negative (pull bot down)? Does it depend on value of "gravity"? In theory it should, but I don't know if that was implemented?
About moving factor - it certainly is somewhere in the program - I can see the effects of it. Set it too small and bots don't move at all, set it very high - they run like crazy.