Do you tanks have an REE number stamped on them? If they do, then doing the "+" takes just a couple minutes more doing one simple math calculation. No other tests or equipment required. Which means getting it hydroed can be a good opportunity to try and educate a local shop, rather than look for another distant one.
Some shops admittedly could care less about scuba work, let alone learning anything new, and just aren't interested in doing the plus regardless, but others can often be talked into it, especially if you can present it as a challenge to their professionalism, or make them realize that it could let them tap a market no one else in the area is tapping.
