By definition, all CIM transactions are recurring, so the 'recurringBilling' flag should be set.

This flag will notify the processor that this is a recurring transaction, so it can ignore AVS/CVV and other verification checks.

From Authorize.net:

The "Recurring Billing Transaction" flag set when submitting a transaction through Authorize.Net is an informational flag that we will send to your processor. It is important to understand that setting "Recurring Billing Transaction" to true does not mean that Authorize.Net will bill this customer again. If you would like Authorize.Net to rebill customers automatically, you may want to look into the "Automated Recurring Billing System". More information about this service can be found in your Merchant Profile.

Setting the "Recurring Billing Transaction" flag to true when you submit a transaction to Authorize.Net actually does not directly affect the way that we process the transaction at all. It is dependent upon your processor how this flag will affect your transaction. One common example of how this affects transaction processing is that it may disable the Address Verification Service. Some processors assume that if the transaction is marked as recurring, you have already verified the customer fully and so the transaction verification status is marked as not applicable to the transaction.

For specific details on how this flag will affect your transaction, it is recommended that you contact the merchant services account that set up your processor for you. They will be able to contact the processor for you and determine exactly what response you will see.

See Authorize.net CIM documentation for usage.