OK, thanks again emcampbe and IAH-OIL-TRASH for the screenshot / info. Sorry for my ignorance of this basic information

My understanding now is that any SFO <-> EWR flights I take as Gold will not be eligible for CPUs and I am also not eligible for instant upgrade if I buy Y or B fares for this route.

The only way to get into business on this flight would be:

1. Using a RPU
2. Using a GPU
3. Buying up with miles
4. Buying the ticket in first

Does that apply to all status levels, including GS?