yes. It is especially for us very hard to keep the 5.1 sound. We haven't yet found an accurate way to keep it and so all CBB edits will be 2.0 until there is a program that is able to do what we need. For "War of the worlds extincitve cut" it was anyway impossible to keep the 5.1 soundtrack, because we remade the audio in a major way, including voiceover and hundreds of sounds. The last 15 minutes were resounded and rescored from scratch.
Some editors use vegas to reconstruct 5.1 from 2.0 but that is only a foul compromise IMHO.