Question about normal (not alternative) curve compression

[AgeOfPanic]

I am working on a movie now. It will be three CD's with DTS sound. My first encode, based on the settings in the Snowbeaches guide, looks pretty good, but there seems to be some blocking in the low bitrate scenes. I read a lot of topics about the issue of alternative curve system and the consensus seems to be not to use it, unless you want to experiment.
The guide also mentions the normal curve compression, which you can use to redirect some bits to low-bitrate settings. Is this option any good or does it have the same disadvantages as the alternative curve system?
If it is good, what are normal values for these options? And also which should I use: The "High bitrate scenes" or the "Low bitrate scenes" settings.