there are so many theories that abound as to how to press, prepare and treat a bat. In Oz, it differs not just from state to state, but from area to area (read, retailer to retailer) and it must be the same wherever cricket is played. the theories have been evolved from accumulations of information over generations and the end result is that there is no one theory that ends the argument. you can however be sure that if the bat is being supported by a lump of foam or an old bed spread, if the roller is not an exact match to the face of the bat and if the pressure being applied cannot be measured, the result will be a mystery!
Learning from history and sudying data gained from testing must be a plus.