"One Year Later" Before "Infinite Crisis"?

Did “One Year Later” issues of on-going series start coming out before “Infinite Crisis” finished? Superman #650 (" Up, Up, and Away! Part 1"), for example, has a publication date of May 2006, and an on-sale date of 3/15/06, according to comics.org, while issues #6 & 7 of “Infinite Crisis” apparently didn’t come out until 4/5/06 and 5/3/06. Is this true? Or does comics.org have the wrong dates? Were the last couple issues of “Infinite Crisis” delayed or something? Wouldn’t readers at the time have been confused to start reading “One Year Later” issues a couple months before “Infinite Crisis” concluded?

This is correct. One Year Later did start publishing before Infinite Crisis was over. The whole idea was to create a mystery of “Wait, what happened in the middle?” and draw people into Infinite Crisis- and, subsequently, 52- for answers. (Which… didn’t actually come, in most cases, and usually had to be resolved through context clues or flashbacks. But hey, what 52 did end up being was much more interesting.)