That's a bit weak, but they only have a .33% chance of hitting the jackpot (based on ~300 active miners) IF they are mining when the jackpot falls, and at "5 MH/s" on triplemining, they are CPU mining (5 MH/s is the lowest most pools will show because they average on 15 minutes), so that "5 MH/s" will come and go evn further deteriorating that user's chances, because a CPU miner doesn't return shares fast enough to keep the site convinced it is still mining (I've seen two GPUs mining at well over 8MH/s each [so at least 16.5 MH/s total on one worker] show 0 MH/s becaues it took so long to return a share).