I think dealers must get some great deals on basic WDH kits. The best dealers get good deals on better hitches (with integrated sway control) for their customers.
With a trailer that long and heavy, I would at the very least get a 2nd friction sway controller on the other side.
Most people today that need weight distribution go straight to a system with integrated sway control. You should consider the Equal-I-zer, Reese Dual-Cam, or Blue Ox.
thebrakeman ('70), DW ('71), DD ('99), DD ('01), DD ('05)
2004 Surveyor SV261T (UltraLite Bunkhouse Hybrid)
2006 Mercury Mountaineer V8 AWD Premier
Equal-i-zer WDH (10k), Prodigy Brake Controller