The Servicer object in the AccountId response is the LFI that is servicing the account (the LFI where the account is held). So may be the BICFI for the LFI itself.
The beneficiaries and scheduledpayments resources have the CreditorAgent object, where the BICFI may be used. This is not the Servicer of the AccountId (and there is no object in the beneficiaries and scheduledpayments resources called Servicer).