Exactly that. You can reduce the truly random nature of dice rolls by adding multiple dice to create that bell jar result. So with two dice you are more likely that your figure will move between 6 and 8 inches (or cms), but you ensure anything else they do is restricted, ie, can't fire, fight at a decreased effect, etc, so you have to make a choice of moving between 1 and 6 inches (1D6) and being able to do something else or an average of 7 inches (2D6) but having restrictions. I am surprised that wargamers have no issue with using dice in calculating firing and combat results, but not for movement when there are an equal number of factors that are at play to speed up or slow someone down.