Replacing leaf springs or installing helper springs

After incurring a flat tire on our last trip, the technician who replaced the flat with my spare showed me why the tire went flat and mentioned the need to either add "helper springs" or replacing the leaf springs. Has anyone on the forum done this and if so, was it that expensive? I have a double axle 5th wheel with the equa-flex system (2007 Crossroads Cruiser). Appreciate your advice.