Just happened to notice a big full-page ad for the first Fiends of the Eastern Front novel, Operation Vampyr, written by Dave Bishop, based on the classic 2000AD series about Russian vampires on the Eastern Front during WWII. And part of the ad reads:
"Black Flame's first novel in a bloody new trilogy, Fiends of the Eastern Front: Operation Vampyr features historically accurate battles and all-out bloodsucking action!"
Well, historically accurate battles apart, one assumes, from the vampires.
And really, Russian vampires during WWII is a pretty neat sounding concept for a story. If you're starting with that, is it really going to be that much more of a selling point if the battles are historically accurate?