I don't think an asset sale HAS TO coincide with the POR, but it seems like the POR would take a whole lot of work and they would not want to have to do it twice, which a major asset sale might require (I am not an expert on bankruptcy law, so I say "might"--but this seems logical).
Therefore I think they would try to put it forward as a done deal in the POR if they could, rather than having the POR be a moving target that potentially required a lot of rework.