Though I think (anyone feel free to jump in if I’ve got it wrong) that the coffee limits are not 10% non-coffee matter by weight but rather 10% of beans demonstrating insect damage/infestation/mold. This is not exactly reassuring, but it’s almost certainly far less insects than 10% of your coffee bag’s weight being ground up buggies. You can read about the FDA’s coffee analysis process which is interesting, if somewhat opaque.