Neat A/B comparison. It’s definitely what I’m hearing with mine as well, the 2015 is generally a bit brighter with more detail in each note than my 2013.
However, correct me if I’m wrong, but I was under the impression the 2015 toggles were to cut from full humbucker to single coil on each individual pickup, not to go from series to parallel as implied in the YouTube clip. Also, sounded like the YouTuber recorded two sets of both/neck/bridge examples for the 2015 but he called both examples “series”. So not only is he mistaken about the switch functions but he didn’t correctly call out which example is which switch setting. Knit picking aside, it did accurately represent what I hear with my 2015 vs my Anniversary bird.
And now the interesting and odd ball quirk that I have with both my 2015 Tbird and my 2013 EB5 (which has the same pups) - if I play either bass for more than an hour straight I get a ripping migraine headache. None of my other basses have that effect on me even if I play them longer and louder. It’s really bizarre. Can’t explain why it happens. I sometimes wonder if there’s some sub sonic or possibly super high frequency or microphonic noise emitted from those pups or maybe a unique pressure spike at a specific frequency that I can’t readily hear but that somehow stresses out my ear drums. Doesn’t seem to effect my wife at all, just me.
The good news is I haven't heard any voices in my head yet telling me to buy more Thunderbirds.