Weight fluctuations are caused by many things (hormones, water retention, muscle gain, time of day) and this makes it hard to lose a set amount each week.
Over a 4 week period however, your weight loss should average out to be in line with your target weight loss.
Of course, you need to stick to your target calorie allowance and balance your week-to-date calories that can be viewed in your Weekly Summary report.
Follow your progress by viewing your Weight report. The graph clearly charts your actual weight against your target weight making it easy to track your progress.