Hi,
Low Grade Fuel (and inventory) is not refunded anymore when crashing, or killing (/kill mini) a vehicle.
We tested with modular cars and minicopters and scrapcopters.

Config is for minicopter:

"Mini Copter Vehicle": {
      "Purchasable": true,
      "Display Name": "Mini Copter",
      "Use Permission": true,
      "Permission": "vehiclelicence.minicopter",
      "Distance To Spawn": 8.0,
      "Time Before Vehicle Wipe (Seconds)": 3600.0,
      "Exclude cupboard zones when wiping": true,
      "Maximum Health": 0.0,
      "Can Recall Maximum Distance": 0.0,
      "Can Kill Maximum Distance": 0.0,
      "Minimum distance from player to recall or spawn": 2.0,
      "Remove License Once Crashed": false,
      "Commands": [
        "mini",
        "minicopter",
        "copter"
      ],
      "Purchase Prices": {
        "scrap": {
          "amount": 10000,
          "displayName": "Scrap"
        }
      },
      "Spawn Prices": {},
      "Recall Prices": {},
      "Recall Cooldown Bypass Prices": {},
      "Spawn Cooldown Bypass Prices": {},
      "Spawn Cooldown (Seconds)": 10.0,
      "Recall Cooldown (Seconds)": 10.0,
      "Cooldown Permissions": {
        "vehiclelicence.vip": {
          "spawnCooldown": 900.0,
          "recallCooldown": 10.0
        }
      },
      "Amount Of Fuel To Spawn": 0,
      "Refund Fuel On Kill": true,
      "Refund Fuel On Crash": true
    },​

Sorry for the late fix 😘

Thank you 🖖😀