The robust B.O. business that has characterized 2013 thus far appears to be losing energy as Paramount-MGM’s “Hansel & Gretel: Witch Hunters” is expected to slay the domestic B.O. this frame with modest results. Pic earned $6 million on Friday.All said, the Par actioner is expected to go home with around $15 million this frame, more than $5 million short of its pre-weekend estimate, but still enough to take top spot. The film was pushed back from its original release date to accommodate a post-conversion to 3D, which accounts for 86% of its screens, though 2D vs. 3D figures are not yet available. Across the board, lower-than-expected grosses will likely make this frame the first to disappoint its 2012 predecessor, though not by much, when Open Road’s “The Grey” won the weekend with $19.7 million and three other films broke $10 million. The only other film now expected to surpass $10 million this frame is Universal’s “Mama” with $11.8 million. “Mama” took $3.9 million Friday, and its success two weekends in a row — an uncommon feat for a scarer — could be attributed to its PG-13 rating. All its competing newcomers last frame and all the wide openers this frame are rated R. And those R ratings may be the real shot to the foot that is keeping actioner “Parker” and raunchy laffer “Movie 43″ in fifth and sixth place, respectively, this frame. FilmDistrict’s actioner earned $2.1 million Friday and is looking at a three-day haul around $6 million, while the Relativity comedy took $1.8 million for a roughly $5 million haul this frame. Still, Relativity shouldn’t break a sweat this weekend as its $6 million-budgeted “Movie 43″ is already in the black through foreign presales, an $8.5 million bow in Russia and a built-in deal with Netflix. “Parker,” which is a littler pricier at around $30 million, mitigated its risk by toplining Jason Statham, who has tremendous foreign appeal. Filling in the gap between “Mama” and “Parker,” Oscar contenders “Silver Linings Playbook” from Weinstein Co. and “Zero Dark Thirty” from Sony tied at $2.3 million. The pair, which expanded from limited to wide release in adjacent frames, have cumed $61.8 million and $62.4 million thus far, respectively.