I don't know if this is of any interest to anyone but this is something that happened recently.
I bought a bunch of Protank 2s and 3s because I got a really good deal on them. I've only opened one so far, a Protank 2.
I put it on one of my iSticks with the istick's Ego adapter and beauty ring and got a 0.0 reading. Took the adapter and ring off, screwed it directly on the istick, same reading.
I put the Protank 2 on an Ego battery, won't fire.
I put it on my MVP, works fine.
I can see that the center pin on the Protank 2 looks a bit short of the bottom so that's probably the problem.
Yesterday I put an Ego adapter that I bought a long time ago from Madvapes on the istick and tried the Protank 2 again. Works great even with the beauty ring. In fact the Protank 2 sits above the beauty ring slightly.
So, if anyone has had a similar problem, try switching the Ego adapter that comes with the iStick for a different one.
You don't need all the different adapters- Just pull the center pin out just a wee bit.

He also said recently that the DNA 40 technology is too little too late (sic) because we can get cheap 100-watt mods from China for less--and it all comes down to dollars per watt...