It seems weird to me that the software allows you to write multiple answers to a question, let alone your own question.
Occasionally - very, very occasionally - this is useful.
But just because the system lets you do it doesn't mean its a good idea. And in fact, the system will warn you if you try it.
Are you sure you want to add another answer?
You could use the edit link to refine and improve your existing answer, instead.
Answering your own question once in a "here's a different way that worked well/didn't work at all" sense seems like something one should be able to do. Multiple times does seem weird, though turning it into a wiki does counter that oddness to some extent.
At some point you have to rely on the users to behave in rational ways, I suppose.