This thread has reminded me of three times that I've bought a sizable amount of meat or fish from the Mettawa Costco (ribs, salmon, rib roast) and found that the weight shown on the package sticker was significantly greater than the weight I measured at home --- on a digital scale that I bought at Costco. I was going to go to the service desk to ask for the appropriate amount of my money back, but a friend who works there suggested that I instead email corporate with photos of the scale readings and sticker weights and suggest that the scale in the meat department at that location might need to be calibrated. I think she was correct that that's a more productive route to take. I don't want to have to weigh every meat or fish item I buy from there in the future, or worse, take my digital scale with me every time I shop there.
Not that I've found the Mettawa Costco is alone in this. I've also found I've been overcharged for fried chicken sold by the pound from one of the nearby Jewel stores (can't remember which one). I haven't been in the habit of weighing every such package I buy at a grocery store; I must admit it's only when buying something that weighs, say, three or more pounds at $8/lb or more that I start to wonder how much trouble the store went to to weigh it accurately.
I'll also say it's never gone the other way: I've never yet weighed a package of some pricey meat or fish and found the sticker weight was less than the scale weight. I should add that I'm talking about the sticker weight exceeding the scale weight *with* packaging (styrofoam, plastic), which weighs so little it doesn't account for the differences I've seen.
I agree that things like bags of potatoes and carrots can't be expected to weigh exactly to the pound, and I expect them to average out in the long run. Only since this thread was started has it occurred to me to weigh them once in a while. But things like meat and fish, which cost roughly 10 to 50 times more per pound and for which the seller labels the weight to the hundredth of a pound, shouldn't be off by half a pound or more on a five-pound package. I do suggest checking with your own scales at home and letting store managers know when you find a significant discrepancy.
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