IT’S AN OLD-FASHIONED SHOWDOWN: Will the absence of Kanye West’s G.O.O.D. Music compilation album Cruel Summer from iTunes on the day of release affect his chart showdown next week with P!nk’s RCA release, The Truth About Love? That’s what insiders are asking after West’s perfectionism had him pull the album from the Apple site for some production tweaks, even though it remains #1 at Amazon MP3. The album was supposed to return to iTunes sometime today, but still hasn’t. Will the glitch eliminate the slight edge Kanye was given going into next week’s chart? We’ll soon see. (9/18p)