>>And that's in a grocery which prides itself with having the prices also recalculated into per unit prices, so one product being in 7oz bottles can be compared to the other which is in 10oz bottles. But they don't recalculate all the instances of the same product into same units, probably to promote the house brand.
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>By obvious reason I am not a big fan of british system. I'm just trying to adjust and understand people (hosts in some sense) around.

Coming here I was mentally getting used to these weird measures, which seem to have more history than system (why are some divided by 3, some by 2, some by 12, some by 16... makes no sense to me). I've become quite good at switching miles to kilometers and back, pounds to kilos, ounces go a bit harder... and at some point I got worried about converting phases of the moon, and realized they aren't measured at all :).

I'm still looking for a home appliance with a clock on it which would be aware of the 24h day (found only one - thermostat for the A/C). The other thing that still throws me off at times is the Set Date American - the MDY is used only here, I think. I laugh every time I look at Set Date ANSI (American National Standards Institute, no less) - which is YMD :).

>By the way, stores are supposed to have labels with 'unit' price in the same measurement for all products of the same category. I'm unsure if it's federal or local requirement.

Not a requirement in Virginia, only one or two grocery chains do that as a courtesy - the price is per each for packaged goods (in the meat or vegetable department it is priced by equal measures). But even within that courtesy they find ways to confuse the consumer. Another trick is pricing like "7/10$", which would read as "seven of these for ten bucks", but actually means the price is 10/7, i.e. about $1.43 per each. I once had to explain that to a couple of British (!) tourists.