but rather a simple mental calculation error in my opinion.
Let's be clear. That is not what you can see. It doesn't actually take a 'calculation' when you see 3% different of 3*10
9 and see an answer that still has a 10
9 in the answer. It is like it is written in
red showing it is wrong.
Then to ignore the order of magnitude change that makes in the result and the change that makes to the argument used shows just how out of depth he is.