The estimate is not necessarily accurate (and it may be even less accurate if you have only been on battery power for 4 minutes) - additionally, not all processes are being viewed. Some system process(es) appears to be using quite a lot of energy. Could the system still be indexing? (mdworker/mds)
Have you timed the runtime yet? Have you checked the CPU usage to see which processes are using the most CPU resources? I'm not sure what the 2016 models do for battery, but I imagine they are not that different from the 2017s, and I'm getting 10-13 hours with lighter usage on a brightness setting that is about 60%-ish. But notice my energy impact graph doesn't have the high spike that yours does, hence my curiosity if perhaps some system process has something to do with this.