Hi Ceola,
Thanks for posting your concern.
If for example payments account A was setup for the MCC3, then only those belonging under the MCC3's hierarchy can use the said payments account A. If another payments account B was setup for the MCC4, then the same concept should be followed for its separate hierarchy.
To be sure, you need to make the
BudgetOrderService.getBillingAccounts() in order to determine that the payments account you will be using is valid for the hierarchy you are managing.
Let me know if this helps and feel free to write back if you have additional clarifications.
Regards,
Ejay
Google Ads API Team

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