Sorry to hear that... I know the center pin thing helped me with a couple of my aero tanks (Neither of my aero-megas register on my MVP 3--but my MVP 2 doesn't pick them up either, nor do any of my iSticks or my Vamo).Looks pretty wonky that way.
If it had just been the subtank, I might have tossed that off to the coil--on both my MVP 3 and my istick 50w, I never get 0.5; usually 0.7 or so, but I did have one kick up to 1.2 which made me do a double-take, thinking I had put the wrong head in. After vaping it for a little while, it dropped back down to 0.7--and this was all on my iStick.Have tried my kanger subtank with a factory made .5 coil and it's registering .7-2.5. Slightly better than my protank which registers up to 6 now.
Well, I'm out of ideas....