Hmm I guess. I don't see it as that different. They've always employed heavy vocal harmony and if they didn't want to use that vocoder effect due to the reason you said they would just do it naturally. I think they chose the same setlist for the 4 shows to unify it and had stories behind those 15 songs specifically. There's no sense changing a setlist if you're not getting people going to more than 1 show also.