Curious about this one, as we're gearing up to go for lvl 5 soon. But I'm not as convinced that it will be 3 extra Pirate chests, based on the city buff for Jengu at level 6, which gives +100% Pirate rewards. In effect, this would quadruple pirate sailing for any guild holding both towns (which is going to be pretty much every realm for a while, it looks like).