As to abrupt. It's not rocket science...my 10p worth.
You have an approach speed and power, and a body angle to achieve the correct rate of descent. Just at the point you want to reduce R.O.D. with a flare, you apply significant sideslip to align, and wonder why the extra drag from this reduces your energy enough to make it plant on rather than kiss the tarmac? Pretty standard for all swept wing jet transports. By aligning a bit earlier you can ease up the power and reestablish an equilibrium. then when you flare and reduce power it bleeds energy more normally. Hence those that decrab earlier or after landing tend to suffer less "firm" arrival than the last minute swingers.....