I have filled a set of doubles not knowing that best practice is to pp blend in one post, and fill through the same post (makes sense, lol).... I got very different readings from each post... I laid them on there sides and within 24 hrs they evened out, thankfully, as I had a wreck dive planned that weekend.An issue I HAVE noticed, is that if I get partial pressure fills, the reading I get at home is very different when compared to what I checked at the shop, if I don't roll the tanks around a bunch before checking them at the shop. I've seen differences of several percent, which is enough to cause trouble. After the home check, if I go back to the shop, the second shop check is pretty close to my home reading. The ride home seems to mix things up well enough.
My buddy said if I showed up to the boat with different mixes marked on each tank I was gonna get it from everyone on the boat starting with him