BitHigh
You have to understand the slat flap system. The three positions of slat are 1, 2&3 and full. In approach when you select flap1 only slat moves to one and when you select flap3 only flap moves to three. You will notice in the table slat 2 position is missing. That is because it treated as three. What is given under the title FAILURE is the position of the lift device when failure occurred. In this case 1≤slats≤3 is correct, flap lever for landing is3 and
ΔVref is 10kts is correct.