I think the production and Kelly probably choose the VT. Obviously that Misha 1 was set up and I genuinely think they want her in the final because of the M&S ad aswell. I think they alway saw Misha as their prime act in this years show, which is not the case at all as you can tell by the voting.
Janet is not a typical X-Factor contestant or winner really, she openly admits to not like pop music all that much, and maybe XF don't like that