With regards to the -1 corrections there are a couple of things to consider:

1) It's not the process, but mostly the reference and the source that determine the outcome. If blacks are crushed in the reference or the source, they end up crushed in the correction.

2) The dark areas in the -1 preview don't have much detail, due to compression, so by definition any increase in contrast will lead to crushed blacks.

3) The colors in this source are in pretty poor shape.

4) The correction is meant to demonstrate the potential of the method. This correction was done, based on a single Tantive IV frame, assuming the Mike Verta frame is a good reference. So, it is not going to be perfect for the entire film. The fact that it works this well is surprising to say the least, but this is not meant to be a final color correction for the -1 sample.