OK, sorry misread your last paragraph:
The augmentation was done for 3 out of 6 parameter so as the space was already 10-30 °C most additional experiments were in the higher range e.g. in the example 40°C. So I cant even really say from the distribution what it would be for 20-40 °C.
I actually don't understand this paragraph. Could you elaborate on what exactly you did?
Again, to increase, as you provide the latin meaning, can mean to increase the understanding of what is going on inside the design space.
"All models are wrong, some are useful" G.E.P. Box