BASI Mogul Skiing is done on Black-Steepness bumps. BASI even at Level 4 (The top level) tests mainly on a big, rounded line, where the skier picks a round line round a berm.
BASI Mogul Skiing also asks for "Various Lines and Corridor-Widths". One of those lines is "Direct"
These videos by Chuck Martin, offer an approach to skiing direct.