Welcome to the community!
This is a good question, the initial/first NBN service will experience provisioning issue due to possible Location ID mismatched if this is the case we encourage to contact the ISP to avoid unwanted charges on the account.
Note: Every address has its own unique location ID which is required on installation. Also for NBN FTTC, HFC, FTTN will only allow 1 service per premises.
Let us know should you require further assistance.