Big difference between LoseIt and MyFitnessPal?

It depends on what your BMR and normal activity level is. If you're at a caloric deficit of 500 every day (You're eating 1,400 but you need 1,900)... that's 3,500 calories and a pound lost each week. Extra calories you burn beyond that with exercise will lead to more weight loss.

I use this:
http://www.bmi-calculator.net/bmr-calculator/

and then this:
http://www.bmi-calculator.net/bmr-calculator/harris-benedict-equation/

to figure out my daily caloric needs, and I usually just multiply by "sedentary" even though I'm a waitress and fairly active in the gym to give myself a little bit of an edge on this weight loss thing.

I signed up for LoseIt, just for the heck of it. According to its calculation (and not even factoring in exercise), it claims I can lose about 1 pound and a 1/2 once a week by eating 1472 a day.

Now, MyFitness Pal says that if I eat 1472 a day AND include exercise burning 462 calories a week total that I can only lose 0.6 pounds a week.

Which is right?? For what it's worth, I've always thought MyFitnessPal's "predictions" for weight loss kinda off, but I just wanted other opinions.

Since MFP does NOT expect exercise to be included in your selection of daily activity level, it uses different multipliers than any other site dealing with activity multipliers.
MFP also starts with base of BMR using formula from Mifflin St Jeor.

Almost all other sites use Harris Benedict, considered about 5% more inaccurate.

Also, the MFP Goal page, where you gave goals of exercise time, frequency, and calorie burn in setup, have no bearing on the math for weight loss. Because calories burned in exercise don't count until you do it.

So, LoseIt says 1472 + 750 for 1.5 weekly = 2222 non-exercise TDEE. No idea what BMR is or your selection of activity level.

MFP says 1472 + 300 for 0.6 weekly = 1772 non-exercise TDEE. Guessing sedentary selected, so BMR is 1418.

Not really sure how you could get MFP to have goal not on .5 mark.

What MFP is will to do, is allow you to select a goal weight too aggressive for amount to lose, basically allowing your daily net to be well under your BMR, not the best thing to do.

Also, outside BodyMedia or BodyBugg or FitBit, the activity multiplier you selected may have no bearing on reality, which is what causes a daily maintenance figure the deficit is taken off of. So if that is wrong, goal is lower than required, and perhaps unwisely so.