Adjust brightness range in ZHA (illuminize dimmers)

Hello everyone,

I have installed several in-wall dimmers of the illuminize brand (Illuminize 5120.1110 and Illuminize 5120.2110). I am very satisfied with the dimmers. They seem to basically follow the Zigbee 3.0 standard and the installation in ZHA was very easy.

However, one thing bothers me: the dimming levels are adjustable with values between 0 and 255. In the GUI, HA apparently translates this into percentage values. However, the light bulbs already reach maximum brightness from a value of 150. Any setting in the GUI between 60%-100% has no effect.

I would like to define the dimming value “150” as 100%.
In the Zigbee cluster “LevelControl” there is a value ‘max_level (0x0003)’. Changing this value does not seem to have any effect.

My approach is probably wrong. Do you guys have any good ideas?