The manufacturing process is not an exact science. so to make 100 records — they make 200 records and then one at a time check for defects . Come delivery they may have 108 records (good ones). I am required to buy all of them. I will not know until this “check for defects” is done. then they invoice me — then i tell u we have “more” records
https://www.furnacemfg.com/how-to-make-vinyl-record/