As technologist alludes above - there are no such systems on the EX77.
However, it is exceedingly quick and easy to add 'padding' every time you set a timer recording.
When you select a programme for a timer recording from the EPG, you are taken to the timer page , where all the parameters for that particular recording are already filled in. [ Start, Stop time etc]
Take the focus across to the stop time using the East/West buttons of the Nav Wheel and then you can add / subtract time using the North / South buttons.
Dabbing the buttons adds/ subtracts one minute per push. Holding the button down changes the time in 10 minute increments.
It is much longer in the describing than in the doing. It typically takes less than a second to do, once you are used to it.
It will depend what channels / programmes you record, but I routinely add 3 minutes to the end of all timers, and I almost never lose anything that way.