Hey!

It seems that the RefillDelay setting applies to all items in the selling machine instead of only applying to the specific product the note is for.
The only change I want is to have the cloth refilled immediately.
However, setting its refilldelay to "0" makes all products in the machine refill immediately :/ 

Here the json from my data folder:

{
  "VendingProfiles": [
    {
      "ShopName": "Produce Exchange",
      "Monument": "assets/bundled/prefabs/autospawn/monument/medium/bandit_town.prefab",
      "Position": {
        "x": 26.8920078,
        "y": 1.88345337,
        "z": 45.395
      },
      "Offers": [
        {
          "SellItem": {
            "ShortName": "scrap",
            "Amount": 10
          },
          "CurrencyItem": {
            "ShortName": "corn",
            "Amount": 15
          },
          "RefillDelay": 60
        },
        {
          "SellItem": {
            "ShortName": "scrap",
            "Amount": 10
          },
          "CurrencyItem": {
            "ShortName": "cloth",
            "Amount": 80
          },
          "RefillDelay": 0
        },
        {
          "SellItem": {
            "ShortName": "scrap",
            "Amount": 5
          },
          "CurrencyItem": {
            "ShortName": "fish.troutsmall",
            "Amount": 1
          },
          "RefillDelay": 60
        },
        {
          "SellItem": {
            "ShortName": "scrap",
            "Amount": 3
          },
          "CurrencyItem": {
            "ShortName": "fertilizer",
            "Amount": 2
          },
          "RefillDelay": 60
        }
      ]
    }
  ]
}

Is it because all sales in this machine are selling the same item?
It makes sense actually.... I guess I need a separate machine?

Yes, vending machines have only one inventory for all merchandise, so if multiple listings are for the same item, they share stock. The plugin (and also vanilla Rust) will try to stock as much as is needed for whichever listing needs the most. The item will also refill more quickly as it's being stocked multiple times.

Separate vending machines is one option. You could also try to reduce the max stock for a specific listing to one, so the amount of scrap that gets instantly restocked is as low as possible, but this also means that listing cannot be purchased in bulk.