The bar that you're thinking of in INA 212 only applies to people who are currently here unlawfully. Once you leave, INA 212(a)(6)(A) [illegal entry] doesn't apply anymore; 212(a)(9)(B) [unlawful presence] does, though. So Advance Parole addresses that and ignores it, which means that even previous EWIs would (at least theoretically) be able to adjust status upon their parole into the U.S.