Check the website to make sure it is not missing too much functionality, and then offer $50
I accidentally ran the v5 software once and marveled at the "new" interface. And I was able to check my values etc... that I wanted.
There may be an upgrade path for that cable too from durametric. Used v6 cables go for around ~200 so if there is an upgrade path you could go to the later cable in the future if desired.