This is why exclusivity will start at date of Orange Book update:
From Judge Mosses court 9-29:
s that the approval letters signify completion of the FDA’s process for reviewing and approving a manufacturer’s NDA. . . . Some requirements that may remain after the FDA sends such a letter are ministerial and do not affect the finality of that approval. In those circumstances—including when the manufacturer will have to finalize a label to reflect DEA scheduling—the FDA does not need to consider further any aspect of the NDA and so it treats its “approval” as final. In other cases, however, the requirements that remain are substantial and will require further substantive review and approval. In those cases, the agency expressly requires further action in its approval letter as a signal that the FDA has concluded that its process is not yet completed. Although not the only method that the FDA might use to differentiate applications that require no further substantive review from those that still demand some significant approval, the approach the FDA has adopted is a reasonable one. The operative statute makes it necessary for th e FDA uniformly to define the “date of approval,” and the agency drew that line in a reasonable place. The Court, accordingly, concludes that the FDA’s interpretation of 21 C.F.R. § 314.108(a) is not “plainly erroneous or inconsistent with the regulation,” and it thus defers to that interpretation
