From WSJ:

"One of Mr. Lopinto's favorite tricks is to search for "B" fares on American -- a coach fare typically a few hundred dollars higher than the lowest price for international trips. "B" fares upgrade for only 10,000 frequent-flier miles each way, while most coach fares on international trips upgrade at American for 25,000 miles plus $250 each way. Buying the more-expensive coach fare can save miles and dollars, and the "B" fare is fully refundable."

Is this documented anywhere on the AA website?