Continuity mistake: The name plate under the photo of Leo at the Veterans Association indicates that he died on November 24, 1942. Paige's research indicates that Nathan and Rick both died on the same day as Leo, but she later finds out that they were buried at the V.A. on November 22, 1942, two days before they are supposed to have died.
Continuity mistake: In this episode, an invitation to Piper is addressed to 1329 Prescott Street. But in episode 1-7: "The Fourth Sister," the Halliwell sisters put up a flyer for their lost cat, and it gives their address as 7571 Prescott Street.
Other mistake: This entire episode the ghost brothers whine that Leo is responsible for them dying and he left them to die, even Leo believes this. It makes no sense. As we see in the flashback even if Leo stayed to help they were blown up moments later and still would have died.
Chosen answer: Her agent/manager negotiated a special billing as part of her contract. It distinguishes her from the rest of the cast, probably when she became a producer on the show.
JC Fernandez