The new WWE magazine states the following:

“Blockbuster movies. Backyard barbecues. Fat girls squeezed into tankinis. Warm weather heralds all these things, but most importantly it signals the approach of SummerSlam. This year the pay-per-view event comes to Boston, where John Cena will put his WWE Championship on the line, and the man who emerges victorious at this month’s Great American Bash will defend the coveted World Heavyweight Title. Might DX raid the party this year? Anything’s possible at the event that’s given us Boiler Room Brawls, The Elimination Chamber, and lest we forget, Mountie prison sex.”

WWE has placed incorrect promotional material in the past and the WWE creative team changes their plans on nearly a daily basis. WWE Magazine had its copy in place about two months ago and my guess is they went with that then because it was the plan in place at the time.