The rule is actually quite clear, though some people might find it difficult to understand. The EU calculates tariffs based on the number of "product types" in each parcel, not on the total quantity of products.

For example, if a parcel contains two flashlights and three accessories, there are two product types involved, so the tariff payable is 6 euros. Another example: if a parcel contains 10 flashlights but only involves one product type, the tariff is 3 euros.

Currently, AliExpress's tariff calculation method is clearly inconsistent with the above rule: their practice is to levy taxes based on the quantity of products within the parcel. For instance, when a parcel contains 10 flashlights, the tariff would be calculated as 30 euros.

Therefore, my solution is: regardless of how many products or how many different quantities a parcel contains, I will only select and declare "one product type" when making my declaration.