With the very limited data so far it looks like they play more of a "greatest hits with circle songs" setlist in cities with single shows and more adventurous setlists in cities with multiple shows.
That certainly makes sense from teh standpoint of satisfying the fanbase. If a promoter thinks a town can support multiple shows, then there are probably more die hard (buy tickets to extra shows) fans in that city and they will appreciate rarities more.
It might be as simple as that.
In general I am OK with the setlists, but am hoping for a setlist more like the first four than last nights show at Detroit. I am betting on a more vanilla set as it is a single show.
Detroit had multiple shows in the past, but is hit alot harder by the recession than soe other cities on the tour so far.
Dave