I will be 97 miles short of 45,000 so was wondering if they'd round me up to get me to the 45k Platinum boost. If the fare would fall back to what I paid for my next trip (booked a Choice Plus so no change fee), I would re-route myself off the nonstop to add those extra miles, but it would cost me more than the difference between 40k and 45k. And an MR would cost me almost as much as the price difference, so not worth adding one more. So I'll ask, and if the answer is no, as I predict it will be, just stew over it for a bit and move on with life.
But in the OP's situation, I'd do the mileage run in the blink of an eye.