Do compact K3 convection rads of same size have same output across brands?

[Possom]

Would it be reasonable to assume that standard compact K3 convection radiators of the same physical size would have the same output in a 50C heating system across brands?

When I check widely available brands of convection rads of the same size, and use the provided manufacturer outputs they give quite different outputs. I'm using AI to convert the provided figure to delta 50 C if required to compare like to like.

 

[Madrab]

Depends on design really - you would think they should if they are all the same standard but I think the manufacturers all go with their own 'calculations' so to speak.