@To**
it could work either way. Elite used work this way, and you could get an extra year by stamping in right at the end, but they changed it a few years ago and if you re-enter in the last year they now only stamp up to the end of the visa.
The legislation introducing DTV isn't clear on what happens with entries but it does explicitly say extensions cannot go past the validity of the visa.
If I were to guess, I suspect they will only stamp up the end date of the visa. But as Adam says we'll have to wait and see what happens.