Moreover the things you studied during the day revolve in your mind when you sleep. You subconsciously realize your mettle by then. Group studies are only beneficial to ones who are slow to learn. But they're not really that recommended. Neither are night studies. So the combination of both, is surely not recommended.
The stronger a light shines the darker are the shadows around it.
Actually it is a personal choice whether to read in night or the usual hours. Some people are so much obsessed with night study that they will not study in day time however convenient it may be.
Knowledge is power.
During me post graduation I was staying in a hostel. There many people used to sit late hours for studies. But lot of time was getting wasted to go out for tea in between and they used spend lot of time on other things and ultimately their output is very less. But I never practiced that and I continued my timings as usual.
So my advice to students of present day is go to bed early and get up early and read at that time. Your subject and your remembering power also will increase. Don't be awake after 10.00 PM.
Don't sweat the small stuff and it's all small stuff.
'Idhuvum Kadandhu Pogum "
Even this challenging situation would ease