I fully understand that language and naming is always full of historical accident, tradition, connotations, path dependence, drift, fully arbitrary and inconsistent categories, yada yada.
I'm not even asking for an explanation, however reasonable or unreasonable, I don't really care. It's gonna be "it's because originally ...", yeah, sure, doesn't matter.
I just think it's funny, and it will never not be funny, that five-spice seasoning lists eight spices in the ingredients.