The deficit is most likely coming from how you have setup the weight you want to but your target weight. If you set you want be 80kg by end of Feb your deficit will be calculated by the app to bit that goal. When the app says “slower loss” it sounds to me like it’s recommending to lose weight slower and rather set a more realistic date further out and increase your caloric intake. This makes sense because what you are eating now is very low and not really sustainable.