Factual error: When Phoebe was telling Paige that the energy ball did not come from the other house, Paige says she saw it come through the window. She could not have seen it because she was in the other room and the door to Richard's dad's office was closed.
Factual error: When Leo shows Piper, Phoebe, and Chris the "warning label" on the genie bottle, he turns the bottle clockwise, reading from left to right. Arabic is read from right to left.
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