Questions:

[Oruss7]

How rewards works please ?

    rewards:
      waves:
        every:
          '3': feather,bone,stick,dirt:4,gravel:4,stone:4,$20
          '5': iron_ingot:10,gold_ingot:8,384:2
          '10': diamond:1,384:10,$100
        after:
          '7': minecart,storage_minecart,powered_minecart
          '13': iron_sword,iron_pickaxe,iron_spade
          '20': diamond:1,364:32,384:10,anvil:1
          '30': diamond:3,384:5,$120,diamond_sword 16:2;19:5
          '40': diamond:6,384:10,$220

It's seems be random...

[Oruss7]

Note that only one reward is picked at random from the list.