Yaris 2013 hybrid battery SOC 100%

I was testing the reconditioned hybrid battery and noticed that if the SOC is at 60 something%
and I let the car glide down a long inclined road, the battery is charged and the SOC eventually
goes to 100% . I used both Hybrid Assistant and Dr Prius and both show the SOC figures turning red
and going above 80% (to 100%). I was wondering whether this was normal/what should be done
in such situations or is something faulty ? I'm playing around trying to get minivci/Techstream to
work and will try using that as soon as I get it working.