Just upgraded to BBCSO Core - What are the differences between Legato and Legato (Extended)?

I searched the BBCSO page, searched the forum, and searched Google, and I could not figure out what the differences are between the two legato options I now see in BBCSO (Core). I am assuming extended means a few more options but it's not clear what the differences are and when I'd want to choose one over the other. They sound quite similar to me in practice, but I'm noticing regular Legato the "round robins" section grays out, so I'm guessing it's less detailed sampling and perhaps a lower CPU footprint? Just looking to be sure so I can choose accordingly. Thanks!