Where you are looking app or web netbanking i added indusind here on 11 march , today i can see bill generated in cred as 15 mar was statement date but no sms from hdfc bill found already smartpay enabled even no payments in scheduled section all things done on web only no hdfc app usage .Can see in pending/ scheduled payments now.
So can safely say that the Bill shows up in scheduled at least 12+ days before due date.
Bill will be paid on 24th, So 4/5 days in advance.
Info might be helpful for some.
@Dobbiee how many days hdfc takes to trigger new statement amount i directly hit button pay now it showing bill amount available but no communication regards scheduled anyhow last date is 4 april .