The 828 was intended to be a simple inexpensive limiter compressor but we seem to have got the design and the time constants right because it became legendary!
My favourite story was that during a visit to Pinewood Studios I was being shown around their (then new) sound stage with a huge Neve mixer, and there in the middle on a script space was an 828…. they were running the final mix through it because they liked the sound of the compressors! The film they were recording was one of the early Bond films. I know this is true because I was there!
The compressors in the 828 are individual, and so have separate threshold controls. They are really limiter/compressors, they start compressing at a low level and the comp ratio rises as the level rises so at high level they start to limit.
When I have seen a picture of the 2012 I expect it will jog my memory and I will be able to give you an answer 