After test/interview it depends on officer how approves the file and file and que on oath schedule. In my opinion, if officer is satisfied and tells applicant at the end of interview you will receive OATH letter soon, means officer has no further issues or to review the file and approves the application right-a-way or in a day/two and mails oath letter within 2-3 weeks. But if officer says we will let you know after end of interview and does not say the word OATH means the officer will take some to review and sign off the application.. But Scarborough is moving fast..