I think the labels and heights are correct, the A340 is the skinny plane, and is the upper plane in the photo. It's also the overtaking plane. It appears longer in the video, so it's lower.
An interesting optical illusion with contrails means you can't tell which contrail is higher than another, and frequently you get it wrong. It's because they are additively transparent (they only add light, they don't shadow anything behind them - dark regions are holes).