I'm the same height as you as recently dropped 5kg to 81kg due to fasting and cutting starch from my diet. Why wife started freaking out because I was looking so skinny (I'm not remotely fat normally either). I can easily burn 4000 kcal a day. All it takes is one hour on the bike. I burn ~3000 kcal on rest days. You have an endurance optimised build, I have a sprinters build. Everyone is different. Those numbers seem perfectly normal to me.