I'm New to This Whole Troll 2 Phenomenon...

...so if this has been covered, forgive me. But when Grandpa Seth is telling the story to Joshua at the beginning of the film, the main character Grandpa Seth talks about is named "Peter". However, the title of the book from which he is supposed to be reading clearly says "Davy and the Goblin". I can think of several reasons why a "Peter" would be mentioned from the book (such as being a secondary character in the story) but would it not have been much easier on everyone, including the audience, to simply tell the story using the name "Davy"? The name that appears on the cover of the freakin' book? Look, I know by now that any and all rules of logic and reason do not apply to Troll 2, AT ALL, but this issue, appearing right at the start of the film, really does annoy me.