320 to win with 9 wickets in hand and 2 days to go doesn't feel even to you?
I agree. 320 in 2 days is not a big challenge. The only thing to factor in is whether the Indian batsman have it in them to be not daunted by the 400+ target and not let it affect them psychologically. Otherwise 320 in 2 days is very much achievable.
Stretch the game as long as possible?
That could be the only reason that would justify the decision to not enforce the follow on.