TV shows have a beginning and ending signature for programming purposes, and probably other reasons. Why doesn't the DVR record a show based on it's signature? By recording the time slot it's supposed run in, we get other shows ending and miss the ending of the show we want. Sometimes we don't get the show at all. We get a recording of whatever took over the time slot. I don't want a recording of whatever sports event, 60 mins, 20/20, took over the time slot. I want my show recorded from beginning to end. If it gets bumped then suspend the record start time until the program signature lines up to my choice.
I used to miss some shows that I had a timer set to come on after something like a sporting event. I have since learned to edit the timer to extend the recording by 60, 90 or more minutes. Now I never miss what I actually want to watch.
I know it would make things easier if the DVR would follow the time of the show, instead of the time slot, but apparently that's the way Dish does it. I think there was/is some other DVR service that has that capability but I'm satisfied with my work-around.