PP1 settings on FX1 and Z1U

Hello! Just bought a Sony Z1u and an FX1. I usually just leave most special settings off, but reading the Z1U instructions, it says PP1 is the best setting for HDV recording, which is what I do, but it doesn't elaborate as to why it is. I normally shoot theatre performances and dance recitals, so I want to make sure it's not going to be messed up looking or anything. Does anyone know what the difference is between PP1 and the Off setting?