If the statement about the content is understood correctly by me, TIME is higher the longer a song is unplayed. But if this is correct, the "Least recently played" random mode would actually be a "most recently played" one.

TIME is higher the longer a song is unplayed. It's 1/32 of the elapsed seconds since last play: 0 immediately a song is played; 18900 after a week; and 32767 after about twelve days, at which point it's clipped. (So anything you haven't heard for twelve days counts as "ages ago".)

As TIME is higher for a long-unplayed song, that song's "soonness factor" is higher, so it gets played sooner. It is the right way round.

The "soonness factor" sort is a descending sort. That's why you have to use -YEAR to get a shuffle in ascending order of year.

Peter