In reality, there are VERY few manufacturers making cells. Note that what we often call a "battery" is really a "cell". A "battery" is a collection of "cells". Moving along though, there's no need for ProVape to "qualify" other brands. Sony cells are used in a very wide variety of other product battery packs. Think electric cars like Tesla for example. Panasonic is another very high quality cell. Efest just rebrands other cells, but many different "brands" are made at the same factory.
In fact, "AW" (Andy Wan) doesn't make his own cells - he takes other manufacturers cells, tests them to ensure quality, and wraps them in red shrinkwrap and adds his holographic logo sticker. They could really be a Sony, Panasonic, Samsung, etc. Look at all the new cells coming out - VapePower, etc. Think new manufacturers are popping up? Nope - same manufacturer, different shrinkwrap.
So, really what ProVape should be recommending are name-brand cells, including Sony, AW, Panasonic, Samsung, etc. There's absolutely NO reason to stick with AW's. Like I said in a previous post, a 35A Sony VTC5 2600mAH is only gaining you 600mAH over an AW - the high amperage "feature" is a complete waste in the P3 with it's 5A limit, but it's not any better or any worse than any other high quality cell. I'd actually go for as high of a mAH rating as possible in a name brand IMR cell. You only need to worry about amp ratings in small cells like the 18350's - I don't think they make 18490/18500/18650's with less than 5A continuous draw rating.
ProVape's recommendation is far outdated. Back in the day, cells were much lower quality, and that's how Andy Wan got a name for himself with his "qualified" cells. Nowadays, it's pretty much a moot point. Just stay away from cloned cells (there are dangerous clones of every cell made, especially AW's and Sony's), and learn how to recognize the fakes - that's your best advice for safety.
I for one am really glad ProVape decided to let the P3 use flat-top cells, as now I can use my large collection of Sony, Samsung, Efest, and Panasonic cells, in addition to my AW's. The P2.5 and earlier (probably) didn't have electronic reverse polarity protection, which is why you needed a nipple-top cell like the AW - put it in upside down, and it doesn't make contact. Brilliant really, at the time. Now, times have changed, and so has ProVape - rightfully so.
Not so much for their closest "competition" - Evolve. Put a cell in upside down and you'll fry their board.