Coming from Frontier (Elite 2), I find it strange that all the missions talk about commodities in a non-specific 'units' way. Judging by the cargo racks, the game is still explicitly dealing with tonnage, so why does it uses the less meaningful nomenclature of 'units'?
Maybe just me, but the idea of transporting 30 tons of slaves made a much bigger psychological impact than transporting 30 units of slaves.
Maybe just me, but the idea of transporting 30 tons of slaves made a much bigger psychological impact than transporting 30 units of slaves.