CAP 698 Figure 4.1 Wind Component Chart Confusion

[aviation1993]

Regarding Figure 4.1 of CAP 698, part f) says that the chart has already accounted for 50% headwind and 150% tailwind

My question is how does it account for the 50% and 150%, because if i resolve the wind components using trigonometry:
Using the same data in the example:
Headwind = 30cos50 = 19.28
Crosswind = 30sin50 = 22.98
Gives the exact same component values from the chart.
Does this mean that trigonometry also accounts for 50% headwind and 150% tailwind? Or am I missing out something here?

Cheers