Jurassic World director Colin Trevorrow and his writing partner Derek Connolly have lost another round in the ongoing arbitration of the upcoming film’s writing credits. Last week, they appealed a WGA arbitration that ruled that they should share screenplay credit with Rick Jaffa and Amanda Silver, the husband-and-wife team who’d written an earlier draft of the script. On Friday, however, the three-person arbitration panel not only voted unanimously to deny their appeal but also gave Jaffa and Silver an additional “story by” credit, further diminishing Trevorrow and Connolly’s screen credit and residuals. And now they’ve appealed again.

If they lose this latest appeal, the writing credits will be: Screenplay by Rick Jaffa & Amanda Silver and Colin Trevorrow & Derek Connolly, story by Rick Jaffa & Amanda Silver, based on characters created by Michael Crichton. If the WGA determines that there was a flaw in the arbitration process itself, however, a whole new team of arbiters could be brought in to determine the final credits.

WGA LogoAt stake is not only the prestige of a solo “written by” credit for team Trevorrow & Connolly but a boatload of future residuals as well. In many cases, writers of successful films can earn as much money in residuals as they received in their initial compensation packages. More credited writers mean fewer residuals per writer.

In its tentative notice of credits sent to the WGA, Universal Pictures originally had proposed that Trevorrow & Connolly receive a “written by” screen credit, with author Crichton to receive a credit acknowledging that the film was based on characters he’d created in his novel Jurassic Park. That “written by” credit, which appeared in a trailer shown during the Super Bowl, meant that Trevorrow & Connolly had written an original script not based on any other source material. That same “written by” credit was awarded to the writers of the previous sequel, 2001’s Jurassic Park III.

Jaffa and Silver, however, filed a protest with the guild, and the arbiters agreed unanimously that they should receive a “screenplay by” credit, meaning that their script had been the source material used by Trevorrow & Connolly, and that no one should receive a “written by” credit. And when Trevorrow & Connolly appealed, the arbiters not only sided with Jaffa & Silver but gave them an additional “story by” credit for good measure.

Had the guild approved the tentative credits originally submitted by Universal, Trevorrow & Connolly would have received 50% of the writers’ share of future residuals, minus the percentage that will go to Crichton’s estate. If the arbiters’ latest ruling stands, they’ll each receive closer to 20%.

Sources say that Universal doesn’t have a dog in this fight and is OK with whatever credits the guild finally decides on.