"Never under any circumstances exceed 10,000 miles" and "we recommend 10,000 miles" are not the same thing. One insinuates you should be changing the oil long before you get to 10k, the other insinuates that you should wait until 10k to change the oil.
One of these statements is in the manual, the other isn't.
My oil life monitor hits 0% prior to 7,500 miles in most cases, which is about right for an oil cycle on a diesel engine. Diesels need fresh oil more frequently than gasoline engines because of the possibility of water, fuel, and soot contamination in the crankcase.
Also, what is it about the Quaker State oil that worries you? The virgin analysis on it shows a much more robust anti-wear package than the other oils guys commonly use on these engines. I suspect it'll hold up very well over time, and I'm about to find out for sure this summer with heavy use and analysis.