That's what I get for using an online calculator.
Still I've got almost 40,000 FLAC files of various quality levels with a duration of roughly 2,700 hours taking up only 1.2 terabytes. Still within the same order of magnitude and still plenty of space in 2TB for a collection I've been curating for 25 years. I don't think it's worth my time to suddenly manage a lesser quality copy of each of those just for a portable player.