persistence of vision would allow that pulse to deliver the full brightness for that brief period.
so the calculated total current is not the same as perceived brightness.
also, if you run your LED's at 2.5 times the current, you should be in the safe zone (80%) of the maximum and be able to put out a much brighter pulse. so much brighter that you would perceive it to be brighter, but it would draw about 1/4 of the current.