The power category or class for different contests is entered into the `Power/Class` field in the setup screen. For example: In the ARRL November SS and ARRL 10M Contest: A=Low, B=High and Q=QRP. If the multiplier is applied automatically in the selected contest, entering A, B or Q in the setup will multiply your score by the value called out in the sponsor`s rules. Example contest: A=Low power x1.5, B=High power x1 and Q=QRP x2.
Read about bonus points.