Even though MGM debtholders seem to be favoring a merger with Spyglass Entertainment, Lionsgate underscored in a regulatory filing on Monday that it could reduce costs by $100 million and boost cash flow by $400 million over the next six years if the debtholders would instead approve its own merger with the storied studio.The letter from Lionsgate to MGM’s management and creditors arrived just days ahead of Friday’s deadline for the creditors to vote on a plan to put MGM into a pre-packaged bankruptcy and have it emerge in combination with Spyglass. If creditors approve the plan, it is not clear whether they would continue to consider the Lionsgate offer, which could give them a 55% stake in the new company. With Spyglass, creditors would own 95% of the combined entity. Lionsgate said by joining forces with MGM it could save $100 million a year from a combined operation, including trimming the workforce by 176, to 699. Under its plan, Lionsgate said its topper Jon Feltheimer would serve as CEO of the new company, and that “the best of breed” between Lionsgate and MGM would fill out the other top exec spots. The company estimated the resulting library of more than 20,000 titles from a merger would generate $590 million in cash flow by 2016. Lionsgate also said it would put out 16 or so films a year, including four that would be tentpole productions. One area of strength for a combined Lionsgate/MGM would be in TV, Lionsgate said, with the company having the potential to reach 300 million homes worldwide, through such domestic and international services as Epix, This TV, MGM HD, Tiger Gate and LAPTV. Another potential opportunity would be to sell an “all-media rights license,” perhaps exclusively digital, to a distributor in countries like China, France, Germany and India. As part of its filing, Lionsgate offered a chronology of its letter exchanges with MGM and one of MGM’s advisers, media banker Navid Mahmoodzadegan of investment firm Moelis & Co.