This imo is one of the closer to accurate looking scales @10%. Assuming his abs are a bit goofy genetics wise, which is another variable. Some guys get dexa coming back at 8% and you're like wtf, but we can't see how much subcutaneous fat they hold. Also you have to look at the whole picture, for example when my front side is at 10-11% my back still shows like 15%, especially lower back.
From what I'm reading online dexa basically will just ignore skin/extra?