7500 is just fine for rotations...it's a non-critical issue. Whatever makes you happy. 10 to 12K is fine too. It's more important to keep the pressure up. Wear should be pretty even anyway.
For oil changes, the 7500 is fine on a full synthetic, something with a PAO base, but I wouldn't do it otherwise. It's right on the cusp of change or analysis, the additive package can be used up by then. For fake-syns I'd want to be at or under 6K. I would not run a conventional oil in this motor. A quick look shows they are spec'ing synthetic anyway, but what's surprising is the GF-4 or 5 rating. That's a top-tier oil rating.
I use Amsoil in every vehicle lubrication point, engine, trans, diffs, even on the bikes (motorcycles) and it's good stuff. But I still don't like to stretch OCI's (oil change interval). Proven out in dozens of rigs of every type and size, euro cars, jap cars, domestics, and trucks. And the race bikes.
If I were wanting to stretch the OCI I'd send a sample to Blackstone for analysis so I had a better idea how it would fare at 7500 or even longer. For me it's just easier to drain and fill, and costs about $50 whereas the testing is $25. It's like no big deal, easier to just change it.
If y'all want to learn about synthetic lubricants go here, everything you could want to know:
www.boboistheoilguy.com
We change more often because we don't want this in our motor. Both BMW and Mercedes Benz are under fire for recommending such long OCI's in their cars, and resultant premature wear and failure, sludging problems. With a 5-6K OCI the motors stay clean inside for the life of the engine, in many cases well over 200K: