It's not out of line with previous the previous jump: the difference between the originally known superconductors and 'high temperature' superconductors was similarly large. If it is a novel mechanism allowing for it then we would not expect that the threshold would necessarily wind up close to room temperature (TBH, I this makes me think it is less likely to be fraud: I think a fraud would temper expectations by claiming it barely works at room temperature). I do agree it needs backing up, though, it could still be an error or more savvy/brazen fraud.