The HyperChairs voting history seems worth looking at, in light of WCD's comments. For reference, the substitution occurred at #267.
Chairs votes PPS at #127, second onto the wagon behind Awaclus.
(Awaclus moves from PPS onto Chairs at #136).
Chairs has an early 3-vote wagon when PPS votes him back at #140: "Chairs (3): Joseph2302, Awaclus, pingpongsam"
(PPS wagon reaches 3 at #204: "pingpongsam (3): Chairs, EFHW, infangthief")
Hyper unvotes at #271, which is his opening post in the game.
Hyper joins me on Joseph at #274.
Hyper moves to WCD at #294, taking her wagon to 4: "WestCoastDidds (4): faust, Awaclus, EFHW, hypercube"
(By #379, Hyper is the only one left on the WCD wagon).
Hyper moves back to Joseph at #381, pushing him up to 4: "Joseph2302 (4): SpaceAnemone, infangthief, faust, hypercube"
Hyper moves onto me at #465 (faust had only just started the wagon at #442).
Hyper moves back to Joseph at #489, putting him up to 3, whereas Robz was already at 6 votes by then.
So it's definitely true that he never voted Robz, while WCD's case said he did. Hyper [i[did[/i] bounce to me and then back to Joseph, but I'd only consider that to be bouncing carelessly between town wagons if I thought Joseph was townie. It certainly looks like Hyper is an unlikely partner for either scum!Joseph or scum!WCD, though.