So long as you have no debt, it will continue to fall all the way to zero. My FICO has been zero for some time now, and I'm proud of that. Lenders are literally begging to loan me money. I no longer need to borrow money either.
The answer lies in the first line of your inquiry....I am debt free.
You well know debt is to credit is to lending is to score. Now in reverse order remove score lending credit debt.
You're smart, if you simply want a score, go borrow money and pay it back over time.
I have read that credit scores effect insurance rates and other costs as well
If this is the case I might need my score higher even though I intend to remain debt free