I spoke to 'Neil' himself. As you probably know already, the AA coating is the same as AAA, but the ceramic can differ in size and there may be blemishes...a cheaper mug.
Back to this again. I had been ordering the AAAs since January, but there's been a deterioration in quality with my last two orders. The latest batch of mugs have a nasty taper on the bottom half causing me major hassle and wastage.
How straight are the AAs usually? Is it a budget mug with defects?
I haven't used AAA from him for a long time so couldn't compare but the AA were always consistent for what I needed and allowed top to bottom. Main thing is you might have a higher standard requirement than what we require. Unless there is obvious flaw we are happy and that is the case with these. If you inspect very closely for the slightest flaw you might get more rejections. It will all be down to the individual. I haven't been using him much so far this year so not sure if there has been a decline on the AA as well.