It's more likely that there's 1 seat available at 80k and 2 seats available at 136k each and the requirement is that both seats have the same fare, though there's no guarantee that booking 1 at 80k won't cause the 136k availability to be withdrawn. If booking 1+1, note that there are various tail risks at play with respect to IROPS, equipment changes, etc. (e.g. flight gets canceled and you and your companion get rerouted differently, or there's an equipment change to a smaller J cabin resulting in one (likely the 80k booking) getting downgraded to PE).