12841 Coro arrives @ 5 PM at MAS and then returns as 12840 Mail @ 7.15 PM, so that the train doesn't keep occupying the platform for a long time. To change one slot of MAS Mail, even 12841 Coro slot would have to be changed, plus ER might also object to the return of early morning arrival of MAS Mail at HWH considering the many early morning arrivals at HWH. Many complexities are there for the old timings to return, inconvenience of passengers has just take a backseat for the officials.