When to create a new entry?

[lxstuart]

This seemed like the most logical place to pose this question.
I have a DVD boxset which is currently listed here, all the details are correct, the only difference appears to be the outer box art.
Further to this, following the "Buy Now" link to Amazon, I see a third box art.

It seems a little unnecessary to add a completely new entry purely for a different box art, but I thought I should ask the opinions of people who have been here longer than myself.

For context, the entry in question is this one

The four bundled DVDs are exactly the same.

[lsvvb92d]

¯\_(ツ)_/¯