Throwing Dreams Under the Bus?

A strange thing happened in China regarding Obama's brief visit with his half-brother Mark Obama. Background--Mark has a loose auto-biography coming out about growing up with the same father Barack mentioned in "Dreams from my Father" except Mark's version sounds more like "Nightmares from my Father"-- not too many Kodak moments based on the early descriptions.

Obama wrote about meeting Mark in Kenya back in 1988 in "Dreams", but when CNN's Ed Henry asked Barack about their relationship he replied like this:

"Well, you know, I don't know him well. I met him for the first time a couple of years ago. He stopped by with his wife for about five minutes during the trip. I haven't read the book.

Tapper recounts the two meeting in 2008 and again at the inauguration; Obama says a 'couple of years ago'. Does that count for 1988, a mere 21 years ago? If not, does this mean he's throwing his own book under the bus or just Mark?

Obama made it clear his father was no saint, something which CNN's video curiously cut short along with at least one wire service (perhaps that explains why Mark dummied-up and refused interviews before the election along with the rest of the family). But one might think Barack would better remember an encounter from his own expertly written book.