It appears you have the general idea already. The only detailed discussion of maneuver duration that I can find at the moment is in the School of Hard Knocks 2.6 Maneuver Duration, page 8.
"If the GM is interested in a more dynamic approach, the Moving Maneuver Table can be used. The GM determines how many points must be obtained, and how often the character gets to roll. For example, picking a lock might require 600 points, but the character gets to roll every round. Constructing a house might require 300 points; the character rolls each month.
The character makes a maneuver roll, modified by his skill and all other modifiers, not including difficulty. The result should be indexed on the Moving Maneuver Table. If the result is a numeric result, the character gains that many points. Any other good result gives the character 150 points. Any bad results provide the character with no points. In some situations, the GM may even reduce the number of points gained if the maneuver roll is particularly bad."
So, as you can see a lot is left up to GM interpretation. I hope that helps.
