I went in '14 and my memory is lousy, but I don't recall that much downtime that year; did the alphabet get run through more quickly, fewer yellows and reds? I imagine it would be tough to plan a 29-"Main" day of racing down to the second, and they can't move the live feed up if they get done early. There are probably contractual obligations between MavTV and Racin Boys not to step on each other's scheduled events so they don't dare run the risk of running late.
I don't know, just spitballing; I don't think, in this instant-gratification/know-the-results-almost-before-it-happens, connected world we live in that a 2-hour tape delay would fly, though...