Yoda, I'm guessing here, but it would seem to be common sense that by following your teacher's advice you stand to annoy the judges on two points: in the first place, playing only one movement; secondly, performing at an eccentric pace.
It's not unknown to perform a single movement at an unusual tempo just to prove a point (Kaplan recorded only the fourth movement of Mahler's 5th on that basis) but you would have to have a very good explanation for doing so ... better than squeezing that work into your programme, for example.
Your teacher's recommendation here sounds wrong to me, but this is one of these issues where I have to append: "what the hell do I know about it?"