First off, since I can select "Contracts" under Scope for a given Dynamic Form Rule, it really should be supported.
Secondly, since the Contract Type is so limited, and not editable, for some reason, we should be able to extend that based on contract type selection.
Form logic doesn't appear to work on Contracts either, so the only way I could accomplish this is Dynamic Forms Rules, which works when CREATING contracts. But does not work when editing them.
SW should fully support Dynamic Forms Rules in the Contracts module.