The Platinum warranty is also 4K. I'm sure the Ultra will handle your 7.5K or 10K oil changes without any problems and more than likely will handle them better. The stupid warranties are just to get a customer to buy a particular brand and change it on a regular basis. All oil companies with warranties do this, Pennzoil, Quaker State, Valvoline, etc.
Besides, warranties must not mean anything to most on here since most car manufactures want anywhere from a 3.7-7.5K oil change and everyone wants to change it on their own schedule of 10-20K.