Most any premium oil in the market will do a great job if changed regularly as you are doing. 115,000 miles with frequent oil changes is not even a well broken in engine yet.

I would not bother with the so called high mileage oils. As long as you are changing regularly there is no need for them. These oils being recommended for certain mileage engines is nothing but a marketing campaign.

With todays motor oils, one should be alarmed any time that the inside of their engine is NOT squeeky clean. There is no reason for it not to be.

Have a great day,