Our credit card processor discovered an issue on the finance charge calculations for our customers. The variance is relatively small, but they are proposing making our customers whole with a statement credit. I thought there was a requirement for issuing a check, but am not very familiar with credit cards. The largest refund is just under $3.00.

will a statement credit put us in compliance?

Sounds like a breach of contract rather than a APR restitution issue. Making the customer whole with a credit should suffice, but I would follow you legal counsel's lead.