PDM Standard Question

OK, so I think I may be doing something wrong with permissions or in the workflow definition.   I have an Approved state in my workflow, where files sit after approval.   For example a file comes out of development and is "released" to Rev A (at say version 4) so its state is Approved.   Along comes a User 1 and they check out the file.   Edit it and checks it back in so it is now at version 5.  User 2 comes along finds Rev A of the file, checks out the file and gets latest version 5 (doesn't know to check history, why would they?) with the edits (unbeknownst to them) and is now referring to an incorrect file.

Vault view reflects the version correctly (at 5), but the Revision variable on the data card reflects revision  A.  (in the old world or Workgroups this would be A+, meaning it was a modified A) 

So, both of these users have "Admin" privileges (profiles copied from Admin when created.   Is that the issue?   Is there a specific permission that needs to be limited so the files have to transition out of Approved to be able to be modified and checked back in within the Approved state?

Or is this a workflow definition thing.   In our workflow, there is a defined state for changes for Approved files (an ECR state if you will).  Is there a way to define a state to not allow check ins?  

Thanks!