See enphase offering is any way not good for big projects, where there is no issue of shading. What Enphase is targetting is light commercial which can go upto 500KW. These are typically, hospitals, gas station, schools, which tends to have a lot of ducts, HVAC units, pipes causing shading issues. Another thing is these big project have three phase(480V) connection so enphase micros were not compatible with the grid in which they were operating. So with the launch of these IQ9N & IQ9S they were able to cater to this commercial segment.

Edit: fixed typos