I think the weight variation is normal. They're mostly cheaply made in China and I doubt quality control is high on what's essentially a lump of metal with maybe a wrapping of rubber and some plastic bits. I remember I had this York dumbbell set given to me as a present when I was about 10, and the weights were so inaccurate you could clearly see the size difference lol.
I don't care about the precision now, as I train instinctively. 40lbs might feel as heavy as 45 on some days, so knowing the exact weight isn't really relevant.
I don't care about the precision now, as I train instinctively. 40lbs might feel as heavy as 45 on some days, so knowing the exact weight isn't really relevant.