The box explaining the commitment percentage on Area 51 states about the commitment score
commitment score, based on committers' activity on all other sites and how old the commitment is
This leads to the effect that users knowing about the decay of the commitment score can uncommit and recommit to increase their commitment score. I've seen a few users doing that, but the vast majority probably doesn't know about that.
I think the decay of the commitment score makes sense, if someone commits and then forgets about it, he is less likely to actually contribute to the site compared to someone who regularly checks on the proposal. But the current method leaves out commited users who regularly check on the status of a proposal, but don't recommit because they don't know about the score decay.
I propose that the commitment score is reset to the original value every time a user visits the proposal site, instead of requiring the user to recommit. This would still filter out users that never come back after committing, but it would not require users to know the more obscure facts about the commitment score to be counted at 100%.