We could be looking at typos in the patch notes and that the original jp document had "item level 70" instead of the "item level 50" they intended. Only way to be certain is spiritbond a bunch of i48/49, i55 and i70 gear and compare average rates of Tier IVs.
Another funny possibility is that people may start forming CM/Praetorium "slaughter everything" spiritbonding parties.