I find the justification presented for only Vettel having the technology a little strange. It's common to test new systems on one car before rolling them out across the team. If the technology works and is reliable, Webber will have it before the end of the season.
Every weekend Red Bull claims the two cars are the same and Vettel is not given any advantage. Usually they test on one car in the practice sessions to gauge the advantage it gives over the current car but in quali/race the cars are usually (if we are to believe Red Bull) identical. I find the justification in the article regarding money unlikely though.