There is a line written on Ticket: "Departure may change and hence confirm before commencing journey"
Time written on Ticket get void and overwritten practically by updated schedule which may not show in irctc but NTES!!
To update Train's schedule as per NTES is valid coz train isn't gonna follow schedule mentioned at Ticket under such update (that schedule is wrong but IRI follow booking site when it's Train's Run & Station Board when it's Train's Regional Name..strange"!!