Hiho! Glad you're enjoying the mod! ^_^
The value 320 is how randomized value, it goes:
math.random(1, 320) or whatever setting you have set in your mod settings.
The loaders are in the treasure filter, so one would receive them if the RNG hits "loaders" as a reward.
Currently it does not scale at all. It is totally random.
Currently it is only for when player has mined an entity. Let me know if you want robots to also be able to receive random loot.