From 45 down to 10 hrs a week

Ra

my son is 18 weeks old, i have been using the glow baby app to track all his feedings since he was born. he went from eating 45 hours a week and it has tapered down less and less now to this week was only 10 hours. he eats for about 4 - 12 minutes at a time.. (an average of 85 mins a day)

is that enough time for a baby his age to be eating? is he getting enough milk?