Isn’t it true that for small parcels, the final drop should be done in the most damage prone orientation, not always the bottom?
You are correct that the drop test is performed on the most ‘damage prone’ orientation. In order to determine the most ‘damage proven orientation,’ a series of drop tests would need to be performed to determine that orientation. This could be onerous to determine for each different product, so common practice is to drop the package in the most probable orientation that would occur in transport. The most common orientation of impact is the bottom (not always flat) and a flat impact transmits the most energy into the product. This has been acceptable to the industry as a default.