> So basically every single one of the test takers got a perfect score? Or am I misreading this?

Three sessions, not three takers.

> I have to say the article left me a bit skeptical about there being any sort of scientific basis for the sniffing.

I don't know about super scientific basis... but you question peoples' ability to smell food and make decisions about how good other people will find its smell and taste after it is cooked?