But they might just as well get a payment at block 3000. If you're moving your MN's after each payment you will be at the mercy of the variance.
If I am reading things correctly, then while gaming the system, it shouldn't ever take your MN longer to be paid than the good actors *plus 15 blocks, but would have the chance of it taking significantly shorter(*at 1000MN, you could receive payment 985 blocks sooner.)