There is a parallel structure in the last six commandments: killing/lying are acts/words against a person, adultery/lust (coveting thy neighbor’s spouse) are acts/attitudes of sexual immorality, and stealing/coveting goods are acts/attitudes of greed. This vanishes if you follow the “Protestant” numbering convention.
Having said that, it is true that there are no “numbers” in the Scripture, there are multiple - at least 2 “complete” and several other “fragment” lists of the Commandments in the Torah, which are not exactly the same each time, and in the Exodus 20 version, which is the one generally cited, there are 13 or 14 imperative verbs - so obviously some of them are part of other commandments, if you are going to reduce the whole to a Decalogue that you can count on your fingers.