The VF-25 might be specific to the Frontier fleet (developed and deployed there). We already have the mystery of what exactly "SMS" stand for, and what it means. The Frontier fleet, numbering some 10 million people, may be, in some sense, independent from UN Spacey. Or maybe they just wanted to get new fighter into the series. They've been playing fast and loose with Macross for a long time now. Something seeming not reasonable, not probable, or just not fitting in, doesn't mean it is not what is going on.
Yeah, and that picture Valkyrie addict posted has me a bit worried. I could really do without Spiritua and the mystical mumbo jumbo from Zero.
I still think the series would be alot more fun if the Frontier had been a Megaroad class ship still looking to settle some 40 years after its launch.