How much fat should I have lost if I was eating a 600 calorie deficit for the last 60 days?

Starting 60 days ago, I began a very strict diet which consisted on a minimum of 600 calories less than i was supposed to get daily. My starting weight being 193.6 with a height of 6'2" and my intake of calories consisting of about 1800 daily. My diet consists of very little fat only which is olive oil or flaxseed oil, lean protien such as chicken, tuna, egg whites, ground turkey, porkloin etc, and my carbohydrate intake consisting of only low sugar fruits such as oranges, vegetables such as yams, and 1 to 2 slices of whole wheat bread daily. In addition, I started weight training two days a week working out legs, chest, triceps. My strength at the gym has increased significantly since I started this routine but my current weight is only about 3.5 to 4 lbs less than when i started. Is it possible that I only lost 3.5 to 4lbs of fat? Or did I lose more than that and my weight didn't change much because I was also increasing my lean muscle m. Because if I do the calculation: 600 calories x 60 days=36000 divided by 3600 (amount of calories in a pound of fat) =10. I should have lost ten lbs of fat