"NFV" has corrected to 1170.37.SPX at 1,193.88.
I don't know why the large divergences are always such that NFV is below SPX. Once they diverge, it seems very hard to get them within a few handles again.
One thing is clear though, NFV is some sort of eigenvector/eigenvalue of SPX, even when they diverge. The phase between them stays the same, it is only the magnitude that is divergent. I know that I am very close to having a highly accurate description of the forces that move SPX.
If we think in energy/momentum space instead of position/time space (they are equivalent), it may be more rewarding.