John McWilliams wrote:

It's not just about the maths. Way too many other factors affecting IQ,
and I suspect most photographers will soon forget about how equivalent
one framing on one camera is to another body he's used. He'll go for the
highest IQ he can in the moment.

IQ is IQ. But the question the OP posted is about the _math_, as he
stated in the subject. Also, the way it is formulated in the message
body, it is about the math and math alone.

I think the OP knows perfectly well that the IQ is not just about the
math, which is why he made a specific effort to extract and isolate just
the math part of the problem in his question.