If my memory is correct a B2 or T4 flew an asymmetric approach at 145kts, at 600ft you overshot on 1 engine or committed to landing. Once below 600ft you reduced speed and selected flap when certain of reaching the runway. This compared with a 2 engined approach at 120kts with 110kts over the threshold.
Night asymmetric was only with a QFI in a T4, so that meant you could extend the crew duty day to the 2 pilot 16 hours. 3 day trips and then a fourth in the T4 –with engine running pilot change over on the taxiway before 20minutes of night asymetric circuits.