How long have you deleted the spam emails?
Sorry, do you mean you deleted the emails by clicking the "Delete Forever" button? If yes, unfortunately, it does mean deleted forever. :(
They are the same thing. :(
That's basically why Google always shows "messages that have been in Spam more than 30 days will be automatically deleted" and "Who needs to delete when you have so much storage?!" above the content of Trash folder.