Priceline Group and Expedia Inc. brands continue to boycott TripAdvisor’s in-app bookings push even as they do this type of booking for smaller metasearch brands.

That competitive dynamic became apparent as Top10 updated its Top10 Hotels iPhone app, which features in-app bookings from Priceline.com and Expedia’s Venere.

When viewing the Sheraton Tribeca New York Hotel in the Top10 app it gives you the option to book the hotel right in the app, with Venere handling it, instead of having to navigate to Venere.com or another online travel agency.

Under this scenario, Venere processes the booking, is the merchant of record when it is a prepaid booking, and handles customer service.

The same model is at work for the Boston Omni Parker House Hotel, which gives users the options of booking a stay within the app through either Priceline or Venere, although Priceline is listed first.

TripAdvisor Refuseniks

Both the Priceline Group and Expedia Inc. have declined to participate in TripAdvisor Instant Booking, with officials not ruling it out, but saying it isn’t in their interests for now.

It is clear that economics and branding issues are at play in the Priceline Group’s and Expedia Inc.’s refusenik stance toward TripAdvisor Instant Bookings.

Under one scenario, at least, the commissions that Instant Booking partners would pay are contingent on what percentage of the time the in-app option for the particular brand appears, according to a source. A relatively small hotel group pegged the commission rate as ranging from 12 percent to 20 percent, but it could be an entirely different range for a major online travel agency.

Expedia Inc. and the Priceline Group also undoubtedly don’t want to prop up an already formidable rival in TripAdvisor, although Priceline and Expedia brands participate in TripAdvisor in the traditional way as TripAdvisor users navigate to the brands’ respective websites to complete bookings.

Both Expedia and Priceline Group brands participate in Kayak’s in-app bookings program. Kayak, of course, is owned by the Priceline Group.

Momentum?

“We are pleased with the momentum we are seeing globally,” says TripAdvisor spokesperson Kevin Carter, referring to Instant Booking.

On the online travel agency front, TripAdvisor has live Instant Booking partners in TripAdvisor-owned Tingo and Jetsetter, as well as Getaroom and AMOMA.com. In the pipeline are Asiatravel, HotelsClick and Otel.com.

TripAdvisor’s Instant Booking lineup among hotels includes Best Western, Choice Hotels, Compass Hospitality and seven other chains are in the implementation stage.

“We like our recent traction especially with regional international players in EMEA (Europe, Middle East and Africa), APAC (Asia Pacific) and LatAM (Latin America),” Carter says.

During TripAdvisor’s third quarter earnings call in November, CEO Stephen Kaufer said the pace of sign-ups with hotels wasn’t proceeding at an optimal speed because some hotels don’t immediately understand the Instant Booking model.

TripAdvisor is clearly increasing its roster of Instant Booking partners, including hotels and online travel agencies, although it hasn’t landed any of the bigger OTAs, which limits comprehensiveness.

Enabling such in-app bookings is key for metasearch players such as TripAdvisor because it increases the conversions of lookers to bookers, especially those using mobile devices.