Help, I am so confused, BMR daily calories etc

I have a good friend that is really into fitness etc and is training to be a personal trainer. She has some information that she had me use to figure out my BMR and then another formula which I am coping here.... to figure out how much to eat each day.

( okay here is her info)
In order to lose a pound a week you need to have a calorie deficit of 3500. That's a 500/day deficit by either eating 500 less calories, or burning 500 calories through exercise.

Calculate your resting metabolic rate (RMR): your body weight x 10= RMR
Calculate your daily activity burn (DAB): RMR x 20%=DAB
Calculate your daily caloric rate (DCR): DAB + RMR=DCR
Subtract 500 Calories a day: DCR-500=Total calories you should be eating per day to lose 1 lb./week

So here's an example for a 150 lb. person:
150 x 10=1500
1500 x .20=300
1500 + 300=1800
1800 - 500 = 1300 calories a day


My BMR is 1,762 and then my other number is 2380 in regards to calories a day. And she says that in order to loose 1 pound a week I should eat 500 less then 2380.

Now this site calculates that I should only be eating 1480 calories a day.... and that is what I have been trying to stay pretty close to for the past 2 months. sometimes I go over 100 or 200 max but keep it pretty close to the 1480 calories.. So am I not eating enough? I am so confused... I also work out at least 2 times a week cause that is when my classes are and I try to get in another 1 or 2 times a week but usually its just 3 times a week.

Please advise.