A VPS license does not have all the capabilities for a Dedicated Server. In lament terms, it does not have all the features that a regular cPanel license would have. There would be things left out if you just purchased a VPS license, and you would suffer in the long run, of course.
A VPS license does not require a Dedicated license for a VPS, although it would require some type of server management. It would be best from my experience to purchase a full cPanel license and skip the VPS deal.