###General answer There are different "schools" on AU, and below is just my perception.
Personally, I would have mixed feelings to accept my own answer, if it is based on the good work and research of someone else. If what I end up using is mostly an edited version of the existing answer, I would probably either:
Ask/suggest an edit or addition to the poster of the existing answer (preferable), or:
Accept the existing answer and add my own edited version, describing what I changed, how and why. It would depend on the situation.
That, in short, is my general answer.