Extremely Loud & Incredibly Close question

If there's one thing I can't wrap my head around, it's the timing surrounding the disappearance of Oskar's friend Mr. Black. Although it doesn't weigh heavily on the plot of the novel, small details like this bother me. On p. 285, the first sentence reads, "The day after the renter and I dug up Dad's grave, I went to Mr. Black's apartment." We know that when Oskar does go to Mr. Black's apartment, he retrieves a biograph card from Mr. Black's index. We also know that he was wearing this biograph card on his person during his meeting with William Black (a different Black) later that day (p. 295). How, then, is it possible that directly before the grave digging operation, Oskar is able to relate to his grandfather (the "renter") the details of what he learned in his meeting with William Black (p. 302) if the grave digging operation itself were supposed to have happened the day before retrieving the biograph card??

My full review below:
http://www.goodreads.com/review/show/...