Someone else may have a different opinion but I feel 4 hours at 100 without a probe thermometer is not your best option. You have the possibility of growing some nasty stuff and getting sick. I would not have set the temp below 135 with the temp swings you would stay around the magic 140 temp.
At 100 you run the risk of dips into the 80's while the thermostat cycles. I prefer double foil on hot meat and stashing it in a cooler with towels. I have also used the smoker set at 140 to hold meat, i would go 135 in the future because the high end of the temp swings caused a bit of drying.