Thought about putting this in Understanding FICO Scoring, but that wouldn't really make sense. Though there is a lot of discussion of FAKOs over there, so mods feel free to move if you think appropriate (maybe it just goes in Smorgasborg).
Anyway, for those interested, not sure what caused the sudden spike, but maybe it is my late payments aging past the 4 year mark. My Vantage score jumped up to 966. It had held at 853 for a long time at various different levels of utilization. At the same time that the late payments aged, I paid down some balances on 0% cards, going from 40% to 20% utilization. That jumped me to 940. I then paid it down to 10% and that took me the rest of the way to 966. I'm speculating that it was mainly the aging of the baddies because My utilization was optimal (at least for FICO purposes) earlier in the year, but I still had hte 853 score.
This information is probably of pretty limited value. It has been reported that Chase uses Vantage, though not exclusively. I did just apply for two Chase cards, one revolver, and one business charge card. I was approved for both, and given a healthy initial CL on the CSP, but it's gross speculation to say that my Vantage score had anything to do with the approval or CL.
I wish the 4 year mark had done something to my FICO score, but it doesn't seem to have had any real effect. Waiting for these last baddies to fall off is maddening sometimes. They're not really hindering me as I've been able to get approved for a mortgage and additional credit cards, but I just want to have clean reports again. Oh well, only a couple more years.
Congrats! The journey is long, sometimes frustrating and yet exhilarating. I too have found util at 5 or 6% doesn't change my scores much. With Vantage, it seems as though any increase in balances (debt) tanks the score.
When the last one falls off you'll want to dance!