Seems to be working fine on my tank. Growth is quite slow, but at least no algae, and the plants appears healthy. I have only got this running for a few months, so no data on real long term performance. Although, in theory, if the light is bright enough, the plants should be able to get all needed photosynthesis done in a short time. I don't have high light plants. The low light ones are found naturally in valleys & such that may have a short day length, so should work. Don't know if a high light plant would suffer with a shortened photo-period.
My main tank is down to 9 hrs. I am gradually dialing it down to see what happens. <Main tank has fish, so might not work the same as the plant only tank .... so taking it slow ...> Some people also find that breaking up the light cycle gets rid of BBA. They would do 4 hr on, a couple hrs off, then 4 hrs on each day.
