You are fine with your setup. It is common to count the tongue weight for the GVW. With tandem leaf spring axles your equalizer between the axles with equally distribute the load to both axles offering a smoother ride and it won't allow one axle to carry too much of the load.
On rubber torsion axles there is no equalizer so one axle may have to carry more than it's recommended maximum weight. That is why some rubber torsion axle manufacturers recommend that the builder use a factor of 1.25 times the weight rating for each tandem axle.