I understand the argument. They say "use what the police use and it will hold in court" The idea being "police loads weren't enough for you, so you had to jack up to some super round."
However, does this apply to .38 Special? Police carried .38 Special. They also, many of them, carried .357 Magnum. Any reload you did in .38 special out of a .38 Special gun would be less than .357 Magnum loads used by police departments way back when.