thank you kb.
@deported: i am not entirely sure about the interviews being waived for cases processed at NBC. you might want to check the Waiver of Adjustment Interviews in Certain Immediate Relative One-Stop Applications section of this document from USCIS. it lists those cases for which there are interview waivers and the "family pack" isn't listed in that particular category. and this document, more recent, appears to touch upon the topic of interview waivers from an I-864 perspective, even if brief.