It feels like the jury is still out on whether or not you'll be forced to redo the Sphere Scroll to upgrade to a Nexus...although the wording feels like it's just to compensate for the adjustment to i115. I would guess that new relic SBing-thing will divide into categories, like the Animus upgrade had us do (FATEs, Dungeons, Leves). Possibly even Primals and Raids required.