an R3er here, just got the interview invite email on 4/5. haas' admission committee claimed that the R3 invites was kicked off on 4/5 and would be thru 5/4.
not sure about how they arranged the sequence, while i believe the invites are probably sent randomly. just be patient. in R2 Haas even kept sending out interview invites to international applicants only 2-3 days before the decision date.
i'm at the Bay Area and my GMAT score is just around the median of Haas'. hope the info helpful.