BTLew..
I went through the whole warranty issue with my local dealer and Hyundai America after my dealer demanded I do all the 60K maintenance at 30K "or your warranty will be voided". Just like that, they deliberately lie to scare folks into spending a grand and change doing unnecessary work on the car to fatten their income. Obviously, I didn't go for it. I did however, have a chat with Hyundai America about the situation, they called the dealer, then the rep called me back to report he needed a shower after talking to that service manager because he was so creepy. He then proceeded to instruct me to follow the manufacturer's book rather than the dealer's creeps. That means 7500 mile OCI, 60K on the coolants and fluids, belts and hoses as needed, etc., etc.
He also let me know that the dealer facility isn't necessary at all. All Tires Plus, GoodYear/Gemini, Firestone, some Wally-Worlds and some Sears centers have the factory schedules and tasks in their systems and when said scheduled tasks are performed by ASE-certified wrenchers, they are honored as being in full compliance with the terms of the Hyundai factory warranty.
Having dispensed with the dealer, I'd say do a 10K OCI if you feel like it. Use the Amsoil, use whatever filter is specified by Hyundai (a gal I go out with now and then bought a SantaFe with a V-6 and uses a cartridge), buy a few of em at the dealer, by a few cases of some kind of dino or syn to show receipts in the event of a dispute and enjoy your long intervals on Amsoil. I'm a 6-8K OCI-guy in my AccentGT which puts a miniscule load on the oil, it barely darkens in that mileage period and I use my PureOne spin-on filters for 2 OCI. I've cut these open in the past and they simply don't load, blow out or deteriorate over that period.
Utah Bill probably has the best policy of all, 4 or 5K on the cheapest oil and filters, he runs his cars in pretty severe conditions, and never a problem. Point being of course, the base oils these days are so good compared to the past, the engines are so clean inside with fuel injection, the metals, the tolerances, every consideration combined point to longer OCI, less wear and longer service in new cars. Especially the economy imports with their mellow 4 and 6 cylinder engines. It seems a terrible waste for folks doing 3K OCI with new filters on the standard-issue engines of the last ten years. No need.
Of course, now will come along the usual dinosaur era cadre' to remind us that "Oil and filters are cheap, my engine (typically a 100-200HP 4 or V6) is expensive and I'm special" to justify said wasteful 3k OCI.
3K ain't even gettin warmed up. Enjoy the extended OCI, you'll be fine.