My comment makes sense if you lean on REST/HTTP and want to leverage the uniform communication and layered architecture. The more bespoke you get, the less you want to care about what I said above. I interpreted your post as general if that makes sense.

In any case, consistency is key. Personally I think it is easier to lean on standards in order to be consistent. Which is why I made some examples of status codes that can only be formed by an application server. I think "how do I avoid surprises, workarounds and inconsistencies" is a good question to make decisions around what we're discussing here.