I'm thinking about flying back and forth SEA to SFO several times just to get the double Elite qualifying miles. I'm not clear on how the calculation is performed.

It looks like 680 miles between the cities. I think they round up to 1000 for this flight, right?

In the doubling equation: Do they round up first, and then double (680 rounds to 1000, then doubles to 2000)? Or, do they double the 680 (to 1360)?

Thanks for your help!