Fico looks at both individual and overall utilization. So even if your overall utilization is, for example 8%, if you have a few credit cards whose utilization is high, like 55%, 75% and 90%, you will still get a ding on your score for your utilization.
So for the optimal score in regards to utilization your overall util needs to be between 1-9% and you should have more than half of your cards reporting a 0 balance and the rest of your cards reporting with 1-9% util.
