The PTSD assessment I had, had nothing to do with these numbers but I remember GAD and PHQ from when I had my depression years ago. I don’t dare write my numbers here for fear of being identified but my GAD was higher than yours and PHQ lower than yours. I had the tests done every week when I saw my therapist so I could see the numbers dropping. I also had something referred to as WASA, perhaps that is what is called impact scale now as the numbers there aren’t too far apart from yours. Whoever gave you the tests, should be able to explain to you what they relate to.
The PTSD assessment is more to do with questions around how you react to things now vs at another given point in your life. Some of the questions were really random to me but it turned out my answers to them also corresponded to PTSD.