would it be worth neutering my F450 from a 4.88 to a 4.10

Hi,

You could "cheat" and move to an even taller tire. That would be cost effective at the next change. For example I moved from a 225/75R16 to 235/85R16 (had to buy new wheels to do so as I'm an E-450). That had a similar effect to dropping down the ratios--and I gained a couple of percent in fuel economy.