Seems there is a time limit for the post edit function. Could that be changed or even deactivated at all, so posts can be edited by the author at any time? In such a small circle I don't think it would be a problem.
In my German typography board people can change their posts forever, and it's hardly ever misused, but very useful, even if it is for the simple reasons of correcting typos.
Especially among the people here, which probably mostly use a Mac with Apple's auto correct, which can do horrible changes of meaning ;-)