There is a problem with Tsukuyomi in your argument.

It doesn't make Itachi cough up blood because of the Tsukuyomi.

A better example is when Itachi had used the Tsukuyomi on Kakashi when Itachi came back to the leaf pre shippuden.

When Itachi fought Sasuke, he had sickness affecting him. Which Sasuke didn't know about in their fight.