Changing the context of a question, whether you are the original poster or not is something very tricky.
Primarily, you don't want to invalidate any existing answers. If your edits will keep any existing answers valid, then you have significant latitude to change.
There are some other factors to keep in mind though since you aren't the OP of the question.
- The OP is given moderator-like privileges for editing, specifically he can approve suggested edits with a single vote. Likewise, the OP (obviously) has full edit privileges on his own post so he can rollback any edit he wants.
- If you do not have 2K rep and do not have full edit privileges, if you change too much of the post, your edit could have a high likelihood of getting rejected.
The 2nd bullet obviously doesn't apply to you, but applies to the general answer.
However, given the constraints above, editing a questions to improve the context, especially with the goal of getting it reopened, is rarely a bad decision and is usually preferable to asking an almost-duplicate.
Reading some of the comments on your question, especially this one:
@p.s.w.g I felt that this question is sufficiently different to justify creating a new one. – Dave Hillier 2 hours ago
@DaveHillier But still, you posted the exact same answer. Isn't that kind of unfair? – Meryovi 1 hour ago
You are missing the point of duplicate questions. Generally speaking, answers usually are the primary factor in determining a duplicate. Since you have posted the exact same answer, I think that reinforces the fact that it is a duplicate, regardless of the fact that the context is a little different.
Some of the other comments in that same question also suggest that you might be unclear on the concept of closed vs deleted posts. They are different and one does not necessarily mean the other. Closing a post is a prelude to deletion, however, there are a number of posts that have been closed for many years that have not been deleted.
Closing is just a warning sign that the question is not appropriate for the site, but still may be somewhat valuable. Deletion is for questions that offer no value. The upvotes/downvotes on the question, and the quantity and quality of the answers are the driving factors in determining whether or not questions will be candidates for automatic deletion. Moderator/community deletion can occur for any post, but generally will not happen for posts with quality answers.
Another factor in the downvotes on your question is the fact that it is a self-answered post. There are a sizable minority in the community that believes that self answered posts are a form of rep-whoring and are not good for the site, despite the fact that self-answering is actively encouraged.
You should have edited the closed question in such a way as to not invalidate the other answers rather than posting your own self-answered almost duplicate question with a copy-and-paste answer from the closed question.