Does size matter?

Oh, for heaven's sake. Not that!

I'm talking clothes sizes, and in particular, the difference between women's clothes sizes in the US and here.

At 5'7" and 69kg (152lb), I'm about an (Australian) size 12 or Medium. Like 97.8% of the population, I don't remotely match the proportions of the fit models used to design these clothes (I'm more pear than column), but it's generally the best place to start. And even though I now wear more, ah, mature clothes, which are more likely to be generously sized, I know that it hasn't changed that much in the past 25 years. Through uni, I was generally 65kg give or take (143lb) which made me somewhere between a 10 and a 12.

Various size charts (here, here and here) indicate that I should be a US 8 or Medium or 34B, or a UK 10.  However, the Amazon size chart tells me that with my 41"/31"/43" measurements, I'm actually a US 12, or Large. Can you spot the difference?

I've ordered a couple of heavily discounted warm tops through Amazon based on these measurements (figuring that they should be more accurate than some arbitrary sizing). But there's always a good chance I'll swim in them, if the sizing is more accurate.  I'll let you know.

EDITED TO ADD:
After hitting "publish" it occurred to me to go double check the Australian sizes. I know I'm typically a 12, and almost all the clothes in my wardrobe are a 12 (including those that I've owned for twenty-something years). However, according to the Australian Standard Sizing Chart, I am in fact a 14, given my 104/79/109cm dimensions. Heck, even the Target size chart reckons I'm a 14-16, and I know I wear a size 12 from them. Clearly, everyone here vanity-sizes too!

It reminds me of something I heard a while back, that the Australian Standard sizes are based on a study done by a bra manufacturer done in 1926, together with US figures from the 1950s, and everyone agrees it's about bloody time we updated it.