Answered by Shaykh Faraz Rabbani
How many minutes over can a person go over the stated time on a timetable, for the suhur?
One CANNOT eat after fajr time has come in. The time mentioned on standard timetables is binding on those who are aware of it, unless they have a STRONGER legal means, such as if they are out in the countryside and can SEE that fajr time has not come in, and KNOW how to tell the beginning of dawn.
The “end of suhur time” that is sometimes mentioned on some prayer timetables is the recommended time to stop eating. To be cautious, when able one should not eat ideally atleast 5 minutes before the stated beginning of fajr time.