A gentleman named Ankit seems to have changed its PF from 5 to 3, 2 months back for some very strange reason. Hope he was aware that Brindavan needs to be departed from PF3. Its very tough to predict PF for TN, trust me. When TN arrives, Kaveri, Brindavan, DD, Navjeevan, Coromandal, BZA JS, CBE Shatabdi all would have either occupied PFs(exception Brindavan which will be shunted by 7.20 to PF3). Add GT as well to this list on some days if its delayed. I have seen TN arriving on PF5,6,7. With the exception of Hwh mail, Cheran, Shatabdi and JS, DD, ICEs SR doesn't follow a strict PF for any train ARRIVALS as mornings get very messy at MAS.