When support cases are created typically customers need a contract. Currently Acumatica picks any contract (maybe the oldest)
Contracts typically come in two types. An all encompassing unlimited support or a T&M where on demand invoices are generated based on activities. These are two completely types of contracts supporting different methods of support.
Solution. In the Case Class near Require Contract, add a selection for Contract Template as a default. This way when a customer gets a case created, based on the case class, Acumatica will require a contract of a specific template.
Example of what went wrong. We had a customer get free unlimited support for months. Reason being an On Demand contract used specifically to generate invoices for activities (or cases) marked as billable. Support didn't have any billable activities because they thought the customer had an Unlimited Contract.