Yours sounds about right, compared to my experience. The compter aims to keep the charge at about four bars. Less bars means there won't be adequate power when needed, and more bars means that the system is not taking advantage of the available power.
Mine goes to seven bars (first green stage) every day when I go down my 200 foot hill, and it goes to eight bars when I drive on the downward side of a mountain pass.
At the green stages there seems to be noticeably more driving power from the battery both in strength and endurance.
On the other hand, I get two red bars (first stage of red) when I accelerate up over 90 mph, or when I go up through a mountain pass. Only once did I get it down to one red bar, also over a mountain pass.
If you sit in the car without the engine running but with the AC on, it will go down to red bars.
Generally the car is designed so that it takes care of itself, and you can drive it as you like with almost no chance of doing it harm. The computer senses any dangerous conditions you might be heading for, and takes evasive action. What a great vehicle!!