Cluster feeding at night

What does this mean he’s my thrid baby but my first one to breast feed my other two it just didn’t work out. He’s been great no issues at all but lately it starts at 7 he just wants to nurse until about 9 or 10 when we go to bed he’s still getting up his usual amount of times at night only gets up twice feeds for about 15 mins and goes back to sleep. I’m new this so idk could my milk be thin in the evening and not filling him up? Any advice would be appreciated. Thanks! I know I don’t have a supply issue cuz he’s gaining weight just fine.