Unless it's an example of D.W.'s lack of counting skills, then she would also be five in "Arthur's New Year's Eve", as she mentions, "I'll never be Arthur's age, he's always gonna be three years older!" If she were still four, then three years older would make Arthur seven, but we know he's eight, so again, unless D.W. miscounted, then she's five in that one.

But when did they change Mr. Haney's first name to Francis? I haven't noticed this yet, but I did notice the whole Sarah to Leah thing with Mrs. MacGrady... but noticing that "The Great MacGrady" was both written by and dedicated to writer Leah Ryan, my assumption was they changed her name to Leah for that episode in her honor. What I REALLY don't understand about that episode is, looking at Buster's journal thing or whatever towards the end, he documents the day, and apparently it's Saturday June 2... now I suppose Lakewood Elementary might not get out till June like some schools (our schools always got out in May), so that can be overlooked... but why are they at school on a Saturday?