It really depends on people submitting results for the games, which will gradually cause old submissions to be deleted. The only way to help is by submitting your results. I've long given up on manually fixing submissions (there are now nearly 90,000 entries) so it's entirely processed automatically. While the algorithm does favour newer submissions over old ones, it only discards the older results once there are enough new submissions to ensure overall accuracy. This does mean that for some games that are drastically changed after an update, there will be a period of inaccuracy until enough people submit new results