In the wake of Fifty Shades Of Grey and Focus, the term R-rated is becoming an even bigger force at the multiplex. Two more titles with restrictive ratings, Sony/Media Rights Capital’s sci-fi robot film Chappie and 20th Century Fox/New Regency’s Vince Vaughn comedy Unfinished Business, are opening with the box office top 10 slotting six R-rated titles.

After Warner Bros.’ Focus underperformed last weekend with a $18.69M opening drawing a predominantly over-25 crowd at 88%, some distribs and box office analysts are concerned that the glut of R-rated fare will weigh down ticket sales this weekend.

Sony is projecting midteens for Chappie at an estimated 3,200 playdates (718 of which are IMAX and premium large format combined), which marks Neill Blomkamp’s third postapocalyptic sci-fi film after 2009’s District 9 and 2013’s Elysium. The story of a killer cop robot that strays from the pack and develops sensitive feelings, Chappie is expected to open at No. 1, with Focus estimated to fall 50%-55% in its second weekend.

Unfinished Business reps Vaughn’s first R-rated film since 2012’s The Watch with Ben Stiller ($12.75M opening, $35.4M domestic cume), his previous two titles being PG-13: 2013’s Delivery Man and The Internship. The new film, which also stars Dave Franco, Tom Wilkinson and Sienna Miller and was fully financed by New Regency, is looking to bow in the mid-single digits at 2,777 theaters. Unfinished Business is Vaughn’s second corporate comedy, following The Internship, and follows a Euro business trip that goes off the rails for a small business owner and his associates.

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Analyzing the flood of wide adult fare at the box office, Rentrak senior media analyst Paul Dergarabedian says that films with an R rating are “restricting the potential pool of audience to those for whom the content is deemed appropriate. While there are titles like Fifty Shades Of Grey, American Sniper and many other examples of R-rated movies that have been successful, those are more of the exception than the rule. On average you’re naturally going to see the potential for bigger debuts (and total gross) for films with a less restrictive rating. If you’re chasing big box office, you go after the PG-13 rating, but if you’re chasing creative freedom, you push the envelope and accept the R-rating that’s appropriate for the content.”

There is one PG oasis this weekend for adults and art house denizens, and that’s Fox Searchlight’s The Second Best Exotic Marigold Hotel, which is opening at an estimated 1,600 locales with a projected take of $7M-$8M. The sequel to the 2011 film starring Judi Dench, Maggie Smith and Bill Nighy revolves around British retirees in India who are expanding a beloved hotel. The film kicked off in United Kingdom, Australia and New Zealand, where it collected $9.39M last weekend.

There are some distribs who believe that some of the R-rated fare in the marketplace is distinguished enough to stay alive and appeal widely to adults, read the fantastic holding power of Colin Firth’s action film Kingsman: The Secret Service, which is currently at $87.9M, and, of course, Fifty Shades, which counts close to $150M stateside.

Nonetheless, with very few kids on winter break — only 3% of K-12 schools are out this Friday and 9% colleges — Dergarabedian adds: “If the industry is going to release R-rated movies, this is one of the better times to do it with more kids in school and a more adult-friendly environment. It’s simple box office math: You present the content to the most available demographic based on the calendar, and that tells you what is the most advantageous time to release R, PG-13, PG or G-rated films.”