add a new column to the cart object for over sized items that should have the 40 euro extra cost applied.
in the eCart add to cart button, set this new column to 0 for regular items, and 1 for over sized items.
then set the shipping rule as:
Number of items with a specific column value:
If the number of items where 'OverSized' has a value of '1' is '>' a value of '0'
Based on items with a specific value:
Total of 'Quantity' where 'oversized' has a value of '1' 'times' '40'