It's probably one of those cases where you you have to delve into the details. So to take one scenario, if your connection was 90 minutes and therefore the 30 minutes of countable time led to being IDB then you have a strong argument. If other delays pushed you below 35 minutes anyway then the countable minutes won't change the story. But yes, a delay to weight/balance is not extraordinary circumstances, whether it is claimable or not depends on the details.