Include Cancellation Fee when creating Event through API

I created a cancellation Fee using the iMIS interface, I then made a get request to pull the event to see how that cancellation fee is defined in the object. This is what I found

 "AddOnFees": {
        "$type": "Asi.Soa.Events.DataContracts.EventAddOnFeeDataCollection, Asi.Contracts",
        "$values": [
          {
            "$type": "Asi.Soa.Commerce.DataContracts.AddOnFeeData, Asi.Contracts",
            "AddOnFeeId": "{{EventID}}/_CANCEL",
            "Name": "Cancellation fee",
            "Description": "",
            "AddOnItem": {
              "$type": "Asi.Soa.Commerce.DataContracts.ItemSummaryData, Asi.Contracts",
              "Description": "",
              "ItemClass": {
                "$type": "Asi.Soa.Commerce.DataContracts.ItemClassSummaryData, Asi.Contracts",
                "ItemClassId": "MEETING",
                "Name": "Event Function"
              },
              "ItemCode": "{{EventID}}/_CANCEL",
              "ItemId": "{{EventID}}/_CANCEL",
              "Name": "Cancellation fee"
            }
          }
        ]
      },

so I added that to my payload when creating Event but it still does not create that cancellation fee. Is there a subsequent call I need to make to have this created once the event is created?