You really need to provide a lot more information.
Here is how Spark calculates your range and what values they take into account in that formula: www.sparkpeople.com/resource/calorie_calcu
What values was your friend using in suggesting that value? I agree 1900 is exceptionally high for weight loss and seems more of a maintenance range. Was she using your current weight, the weight you want to be, the time you want to lose it in, your activity level, your exercise, and your BMR in giving you 1900 as a goal?