Lumens is a measurement of what is perceived by the eye. Par is a measurement of what a plant perceives and absorb. It is measured by a quantum par meter. There are apps that do this as well ,don't know if yours does read in micro mol (umol) . I do like 125umol from sprout and when the in early veg hit it with 250 and above . I am in dwc so environment plays a big part in light intensity . I have learned that If I have enough available nutrients  and my vpd is within tolerance I can push a plant with more light with out burning. Especially with leds . Dr. Bruce Bugbee , Apogee Instruments..on YouTube really helped me understand light and the effects on a plant. I highly recommend his video lectures(free ones)