A 5 minute add will make a small contribution to the IBUs. Unless you are using a couple ounces of a high AA hop at that point, don't worry about it.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk