My guess is something psychologically on the side of mafia.
In setup A3 they have to be wary of : Cop, Doctor, Jailkeeper, and Tracker.
In Setup C3 they only have ot worry about jailkeeper and cop.
My guess would be that mafia feel more comfortable killing strong town players and strong townreads in C than in A, as opposed to roleblocking them, since it's twice as likely a protective exists in A. Killing strong townreads has good odds of hitting masons, while rbing them won't help.
In essence, in A mafia have an additional, safer tool to use than just their kill. This tool does nothing to masons, but that doesn't stop mafia from changing their play around said tool.
Additionally, a goon flip in C doesn't tell the town which column they are in, and lets mafia have more options of who to bus without accidentally making a solved game in rows 1 or 2.