Once you add versions, you do have the option to remove them as well. You can only add or remove all versions at this time and not one at a time.
If you have already scanned some forms, then you are not able to remove the versions but all forms will scan as version one. I see you have scanned 50 tests for your test.
If you have printed forms for the multiple version test and then create a new test with the same assignment name, you can not scan the forms created for the original test. Specific forms with assignment names on them can only be scanned for the assignment they have been created for in the account.