There really isn't any set rule for maneuver rolls for movement. You can basically do what you feel is right.
As for your example, flat terrain, good visibility, I wouldn't require a maneuver. It's a flat unobstructed path. A stairwell is also unobstructed terrain, albeit uneven. No maneuver there as far as I'm concerned.
What I generally do in the case where there are obstructions (trees, very rough terrain, serious slope, furniture, etc), I might require a maneuver, but the worst non-fumble outcome it that the terrain prevents the desired movement. I tend to use the percent column to determine how much movement was actually achieved.