Not that simple. I try to explain. (English is not my main language).
Ie. Product (X) weight 340g. Wrapping(W) weight is 20g. Norwegian snailmail(Post) have a limit with 350g. Next weight limit is 1kg.
Shipping weight under 350g is USD 4.5.
Shipping weight over 350g and under 1kg is 9 USD
See:
X is 4.5 USD
X + W is USD 9.
It is impossible to add that as a handling fee as far as i can see. If I have:
Product (X) + Product (Y) + Product (Z) in one order and total weight is ie. 320g and + 20g for Wapping the total weight is 340g = USD 4.5
if
Product (X) + Product (Y) + Product (Z) in one order and total weight is ie. 340g and + 20g for Wapping the total weight is 360g = USD 9
Hope you understand what I mean.. ??
If I could add handling weight that wold have been great.