I've read that the interval is supposedly driven by some "intelligent algorithm" that takes into consideration several factors including the amount of power used, oil type, presence of alcohol in the fuel, speeds, etc.. most of my driving is 70 mph freeway under cruise control with me as the only payload, but I do occasionally tow both a travel and a utility trailer - both usually running at 6K pounds and when loaded and taking 100 mile trips. My usual driving yields a solid 17 mpg over a tankful dropping to 10.5 when towing. I've watched that oil life number closely and no matter what I do, it's locked on to 1%/100 miles.
My Wife's Grand Cherokee hemi only has a "needs service" indicator but it can be set for when it comes on, purely on mileage. She's been running an oil for elderly engines since she's looking hard at 250K miles, and has the dealer set it for a 3K interval. (she's a short tripper now- usually in the 11 mile range). That Jeep doesnt use a lick of oil between changes, the only sign the engine is that high mileage is an occasional brief lifter rattle when cold starting.
I'll chat up the "lubrication service technicians" when I see the grease monkeys at the next oil change and see what they know. Maybe you have to belong to that secret society to get the decoder ring. I have a hunch using some ODB-style tool that you just give it a number...