I wouldn’t do it, as I wouldn’t when text is on the recto and the verso is blank.
An exception would be if the page contains something not directly related to the text (a list of other books in the same collection, for example).
Also remember to account the folding when calculating the inner margin: more pages wider margin.

I wouldn't either. Also consider that most books are printed on thin paper and there is some show-through. Your unusual placement of the closing text would be obvious.

Agreed with above, keep the last page in the same position.

The design unity of the book as a whole is more important than balancing any one spread. Breaking the consistency for the sake of one page weakens the conviction of the layout across the whole book.

Agreed, you should design the book as a whole and not design it as a series of spreads. If you made the end spread different, it might look right by itself, but would look off when viewed in context with the rest of the book.

Thanks everybody, that makes sense.

I assume the back of the jacket is all together a different matter anyway, and there text can be centered (even should be) independently from the interior of the book.

Right, the jacket can, and should, have a different layout from the interior.

I wouldn't go as far as saying that you shouldn't consider the grid from the inside pages to provide some sort of continuity between the inside and the jacket, but it isn't necessary or even done all that often. The main consideration for the jacket is that it help sell the book.