The duration table in its stock form say how long it takes to flow x amount of fuel at x amount of pressure, for a stock injector. So it says over 7000uS because for a stock injector that?s how long it takes that amount of fuel at that pressure.
Don?t add 20% to the entire duration table, you will most likely hurt your mpg in the lower end. Add duration in the upper mm3 and rail pressure area.