Are those manufacturers dry weights on the 5er? I'd take it to a scale equipped as it would be after being option out as you want it. Manufacturer dry weights always seem to be on a stripped unit and not include battery(s) or propane or things like AC units. You also need to factor in what you plan on loading as it will affect pin weight. I don't mean to come across as preachy and the Titan is a great truck, just it does not match up well with 5ers due to payload limitations.
Go with the Firestone Ride Rite bags. I have them...work great with only 15 psi. Your Titan will pull that 5'er with absolutely no problem. With my heavier load I stayed in 4th gear...both temp. gauges read the same as if there was no trailer in tow.