The Lambda value of Powerline insulation is 0.024W/mK
The U value of Powerline insulation: 0.024 / 0.05 = 0.48 m²K/W
The lower the Lambda and U value the better the insulation
With a 60mm of another insulation board with a lambda value of 0.037 W/mK
You achieve a U value of only 0.61 m²K/W
This is a lot worse than 50mm Powerline
So a lambda value of 0.024 is more than 30% better than 0.037
Powerline has a better fire behaviour than extruded polystyrene
Powerline has European fire class D where as extruded polystyrene only has class E.
D is better than E.
And even in end use, the Powerline has European fire class Bs2d0
Another advantage of Powerline compared to polystyrene: Powerline does not melt! There are no burning droplets with Powerline.