"Symptoms of the disorder first appeared while he was enrolled at Cambridge; he lost his balance and fell down a flight of stairs, hitting his head. Worried that he would lose his genius, he took the Mensa test to verify that his intellectual abilities were intact."
And subsequently he appears to have decided that having actual accomplishments as a physics researcher and as a popular author on science is much more significant than his IQ score. In other words, what he thinks after he learned more and had real-world experience is that boasting about IQ is for losers, as he said in the much more recent interview.
Preoccupation with IQ is not for losers. But we also live in a world where computers augment our cognitive abilities. And so any measure of intelligence should probably be a combined measure of brain + computer.