I think "yeseros" here means "superfluous", rather than merely "additional". Of course that begs the question, but I think that in general it's a statement of principle, not a rule for practice, though in this instance the AhS gives his opinion on what is superfluous.
(I'd also translate "ein daas chachomim nocha meihem" less literally, as "Torah authorities do not approve of them", or even, riskily, "Daas Torah does not approve of them".)