Yeah, I was thinking about that as I was writing it. There were a couple bits where I really felt there wasn't a difference at all, but in the crime scene scene, I definitely felt like there was a strong difference between how Barry would have behaved vs Wally, where you could tell Barry was very confident and comfortable in a more stoic way than Wally usually acts. Still, the fact that in many other scenes they struck me as similar was enough that I decided to claim they're basically interchangeable, mostly because I think the differences are mostly either subtle or few. You're right though, they're not actually exactly the same.