Automation just does what it is told. My check airman checking me out in the 767 wanted the leg from LAX to SAN one night and using automation ended up 300 feet high at 320 knots when I, the FO, told him to disconnect everything throttle way back and lower the nose when our clearance was 2500 ft. He had no idea how to fix the problem with automation he had screwed up. Hand flying sometimes makes things easy. First you have to know how to hand fly.