Look at Air Canada and Jazz, the flow through is actually written in a mutual agreement but AC decided to stop the pouching momentarily otherwise Jazz would have to cancel many flights and that would hurt both of them. The same scenario goes for FZ and EK, FZ is doing some flights for EK, the ones that don't require the triple, if they keep pouching they will hurt themselves. Think about it like a gardening hose where the Gardner plays with the flow of water depending on his needs.