Kevin Costner’s “Message in a Bottle” and Mel Gibson’s “Payback” each made $10.3 million and battled for the No. 1 spot at a very blah box office this weekend, while “October Sky” ($6 million, 5th place) opened to respectable business, estimates showed Sunday. Two other new releases, the workplace comedy “Office Space” and the bad-girl teen flick “Jawbreaker,” were disappointments. “My Favorite Martian” continued to do steady business after two weeks ($6.7 million, third place). “Blast From the Past,” with $6.1 million, was No. 4. Oscar buzz continued to help two best-picture nominees: The costume romance “Shakespeare in Love” grossed $5.8 million for 6th place, and the re-issue of Steven Spielberg’s “Saving Private Ryan” made $2.4 million for 10th.