will there be a update so the water labs loot will be added to the plugin

My question too!

you have to add the prefabs to ~serverfiles/oxide/config/BetterLoot.json

add these prefabs;

"assets/bundled/prefabs/radtown/underwater_labs/crate_ammunition.prefab",
      "assets/bundled/prefabs/radtown/underwater_labs/crate_elite.prefab",
      "assets/bundled/prefabs/radtown/underwater_labs/crate_food_1.prefab",
      "assets/bundled/prefabs/radtown/underwater_labs/crate_food_2.prefab",
      "assets/bundled/prefabs/radtown/underwater_labs/crate_fuel.prefab",
      "assets/bundled/prefabs/radtown/underwater_labs/crate_medical.prefab",
      "assets/bundled/prefabs/radtown/underwater_labs/crate_normal.prefab",
      "assets/bundled/prefabs/radtown/underwater_labs/crate_normal_2.prefab",
      "assets/bundled/prefabs/radtown/underwater_labs/crate_tools.prefab",
      "assets/bundled/prefabs/radtown/underwater_labs/tech_parts_1.prefab",
      "assets/bundled/prefabs/radtown/underwater_labs/tech_parts_2.prefab",
      "assets/bundled/prefabs/radtown/underwater_labs/vehicle_parts.prefab",  

now edit your loottable to include these prefabs;

  "assets/bundled/prefabs/radtown/underwater_labs/crate_fuel.prefab": {
      "Enabled": true,
      "ItemList": {
        "crude.oil": {
          "Max": 70,
          "Min": 35
        },
        "lowgradefuel": {
          "Max": 50,
          "Min": 15
        }
      },
      "ItemsMax": 2,
      "ItemsMin": 2,
      "MaxBPs": 0,
      "Scrap": 0
    },

unload plugin, overwrite with new json's and load the plugin.