Creating a new customer card - can't change ItemPriceLevel

I am able to successfully create a new customer but am not able to set the "Item Price Level" in the customers selling details to a different level. It defaults every time to "Base Selling Price".

I tried "Level C", "C", "3". Each time it creates a customer but the "Item Price Level" remains "Base Selling Price".

Posting to:

http://localhost:8080/AccountRight/.../Contact/Customer/

Payloads I tried:

{"SellingDetails":{"SaleLayout":"Item","InvoiceDelivery":"PrintAndEmail","PrintedForm":null,"ItemPriceLevel":"Level C","IncomeAccount":{"Name":null,"DisplayID":null,"UID":"d16433ff-50bd-4c62-b8ea-a8a0ce861e54","URI":null},"ReceiptMemo":null,"SalesPerson":null,"SaleComment":null,"ShippingMethod":null,"HourlyBillingRate":0.0,"ABN":null,"ABNBranch":null,"TaxCode":{"Code":null,"UID":"9c589a75-271e-4d49-a149-36c8d01dd235","URI":null},"FreightTaxCode":{"Code":null,"UID":"9c589a75-271e-4d49-a149-36c8d01dd235","URI":null},"UseCustomerTaxCode":false,"Terms":null,"Credit":null,"TaxIdNumber":null,"Memo":null},"PaymentDetails":null,"CompanyName":"Buyer Name 1","LastName":"Name 1","FirstName":"Admin","IsIndividual":true,"DisplayID":"69429","IsActive":true,"Notes":"notes bro","Tags":null,"CurrentBalance":0.0,"Addresses":[{"Location":1,"Street":"Address 1 Address 2","City":"city suburb","State":"SA","PostCode":"5000","Country":"Australia","Phone1":"88888888","Phone2":null,"Phone3":null,"Fax":"","Email":"abc@def.com","Website":null,"ContactName":"Admin Name 1","Salutation":null}],"Identifiers":null,"CustomList1":null,"CustomList2":null,"CustomList3":null,"CustomField1":null,"CustomField2":null,"CustomField3":null,"Type":null,"PhotoURI":null,"UID":"00000000-0000-0000-0000-000000000000","URI":null,"RowVersion":null,"Created":null,"LastModified":null}
{"SellingDetails":{"SaleLayout":"Item","InvoiceDelivery":"PrintAndEmail","PrintedForm":null,"ItemPriceLevel":"C","IncomeAccount":{"Name":null,"DisplayID":null,"UID":"d16433ff-50bd-4c62-b8ea-a8a0ce861e54","URI":null},"ReceiptMemo":null,"SalesPerson":null,"SaleComment":null,"ShippingMethod":null,"HourlyBillingRate":0.0,"ABN":null,"ABNBranch":null,"TaxCode":{"Code":null,"UID":"9c589a75-271e-4d49-a149-36c8d01dd235","URI":null},"FreightTaxCode":{"Code":null,"UID":"9c589a75-271e-4d49-a149-36c8d01dd235","URI":null},"UseCustomerTaxCode":false,"Terms":null,"Credit":null,"TaxIdNumber":null,"Memo":null},"PaymentDetails":null,"CompanyName":"Buyer Name 2","LastName":"Name 2","FirstName":"Admin","IsIndividual":true,"DisplayID":"69430","IsActive":true,"Notes":"notes bro","Tags":null,"CurrentBalance":0.0,"Addresses":[{"Location":1,"Street":"Address 1 Address 2","City":"city suburb","State":"SA","PostCode":"5000","Country":"Australia","Phone1":"88888888","Phone2":null,"Phone3":null,"Fax":"","Email":"abc@def.com","Website":null,"ContactName":"Admin Name 2","Salutation":null}],"Identifiers":null,"CustomList1":null,"CustomList2":null,"CustomList3":null,"CustomField1":null,"CustomField2":null,"CustomField3":null,"Type":null,"PhotoURI":null,"UID":"00000000-0000-0000-0000-000000000000","URI":null,"RowVersion":null,"Created":null,"LastModified":null}
{"SellingDetails":{"SaleLayout":"Item","InvoiceDelivery":"PrintAndEmail","PrintedForm":null,"ItemPriceLevel":"3","IncomeAccount":{"Name":null,"DisplayID":null,"UID":"d16433ff-50bd-4c62-b8ea-a8a0ce861e54","URI":null},"ReceiptMemo":null,"SalesPerson":null,"SaleComment":null,"ShippingMethod":null,"HourlyBillingRate":0.0,"ABN":null,"ABNBranch":null,"TaxCode":{"Code":null,"UID":"9c589a75-271e-4d49-a149-36c8d01dd235","URI":null},"FreightTaxCode":{"Code":null,"UID":"9c589a75-271e-4d49-a149-36c8d01dd235","URI":null},"UseCustomerTaxCode":false,"Terms":null,"Credit":null,"TaxIdNumber":null,"Memo":null},"PaymentDetails":null,"CompanyName":"Buyer Name 2","LastName":"Name 2","FirstName":"Admin","IsIndividual":true,"DisplayID":"69431","IsActive":true,"Notes":"notes bro","Tags":null,"CurrentBalance":0.0,"Addresses":[{"Location":1,"Street":"Address 1 Address 2","City":"city suburb","State":"SA","PostCode":"5000","Country":"Australia","Phone1":"88888888","Phone2":null,"Phone3":null,"Fax":"","Email":"abc@def.com","Website":null,"ContactName":"Admin Name 2","Salutation":null}],"Identifiers":null,"CustomList1":null,"CustomList2":null,"CustomList3":null,"CustomField1":null,"CustomField2":null,"CustomField3":null,"Type":null,"PhotoURI":null,"UID":"00000000-0000-0000-0000-000000000000","URI":null,"RowVersion":null,"Created":null,"LastModified":null}

Is there a way around this or am I not putting in the correct value into "ItemPriceLevel"?