I mailed both my K1 and K2 AOS in the same envelope, with 2 separate checks, on Oct 20 to the Chicago Lockbox. They cashed the K1 check and sent NOA1 on Nov 7. They still have not cashed the check I sent for my K2. So from what I'm reading is that it can take 30 days to cash that check even though they were sent together in the same envelope?