I haven't been able to find much through Google about processing credit card refunds... I don't mean chargebacks, where there's a dispute. In this case it would be cancellation of a pre-paid service, where the customer would be getting back a prorated amount.

Is the processing fee for this kind of procedure typically just the same as for accepting funds? Or is it in fact more like chargebacks (which can be pretty expensive)?

The cost is the same as a standard transaction. It has nothing to do with a chargeback.

Thanks, vizi. I was able to find some information from payment processing providers also... One charges nothing for refunds/credits, while another charges $2 per credit. (Both are Canadian payment processing providers.)

Some providers may also charge you the discount rate on the refund instead of a per refund charge. None should penalize you for a refund however, unless you have an unusually large number of refunds consistantly.