Topkart Rotax Exhaust Mounting

So I am restoring one of my Topkart Rotax’s that I was given and have a question about the exhaust mounting. As you can see in the picture there is a bracket mounted off of the anodized alumumium piece that comes from the frame mounted tube. My question is why wouldn’t or couldn’t you mount (with another fabricated link bracket) from the flat bracket that is welded to the frame tube? Seems to me that this would be the reason for this bracket anyway.