At the moment composites are considered an extra item when the weight of the parcel is calculated.
Eg: ABC-COMP (weight 80 grams) is a composite made of ABC-1 (weight 50 grams) and ABC-2 (weight 50 grams).
Linnworks is going to work out total weight is 180 grams (50+50+80) when sending the parcel.
The request is for the weight and dimensions of a composite to override the weight and dimensions of the children.
So in the previous example, total weight should be 80 grams as it is the weight of ABC-COMP (the composite that is made of both SKUs).
We have been advised to use 0 as the weight of composite but this does not reflect reality. To use a negative number would be more useful.
The reason is when selling composites, we can remove extra packing material from the parcel. So a composite will generally weight less than the sum of its parts.
The same applies to packaging: composites are created because they will fit in certain packaging, so the packaging defined at the composite level should override the packaging for each child SKU.