It isn't go/no-go situation. Your 16.7% will work fine but take the battery to 90 percent state of charge most of the time. And to 100% at least every 10-14 days.
You do not want sulfation meaning occlusion of the plates to harden -- it's similar to what happens to flooded batteries. I threw a freakin' fit at Optima in 2005 over this. I also pleaded with Concorde. They soon saw the light. And publications changed. They damned well knew who I was -- the tame tiger who eats the guy with the whip.
Below 15% of amp hour total is no-no. But 15% to 20% can be made up with fuller recharging above 85% - 90% and like with anything chemical TIME enters the picture in all facets of chemical reactions. Cheat one thing a bit and it has to be made up by percentages and time on the other factors.
Chemistry is cruel. It doesn't care if I agree with it or not. Knowing more throws more loops of slavery and dire knowledge of consequences around me. Don't cheat on these values is my recommendations BFL13. The charge percentage and recovery minimums are at the bitter minimum of acceptable limits.
Let those who ***** and moan about having to LEARN (adjacent to kiddieporn in their mind for utter repulsiveness). I do not have the money to be be dismissive about ignorance or learning. You wish to learn BFL and I am happy to share.