I've come across information suggesting that installing HD Radio at my station would enable me to operate a commercial HD-2 station. Can this be confirmed?

This statement contains a misconception. It’s important to differentiate between broadcasting and subsidiary services. Broadcasting encompasses services that can be received using a standard radio, without any special arrangements or subscriptions. On the other hand, subsidiary services are not accessible to the general public and necessitate a subscription for reception. In digital television, multicast streams are considered broadcasting. This same argument could apply to multicast digital radio. Since these streams can be received with a standard HD radio without any subscription or access control, they are classified as broadcasting. Consequently, they would remain subject to the non-commercial requirements outlined in section 399B of the Communications Act.