I think you may have misunderstood his question. I could be wrong but I believe he's asking if he get's the new v5 via NON- upgrade can he move the old v4 to another machine.
I would think that if he purchases a new v5 with keys at a non-upgrade price, he can de-activate v4 on the existing machine (know what keys are for v4) and install it on a new machine and activate it then install v5 on the old machine where v4 was before and activate it. That's strictly a guess.
In any event, I'd wait until the dust settles; judging by several new threads today on June 1, there seems to be some initial issues with the upgrade process and also new, clean installs (non-upgrades). Let's give Ken time to straighten things out.