Hi Ruth.
In relation to your initial question, I didn't say 1,100 net calories a week burned isn't optimal, I said it's not necessarily optimal, but then again it might be a highly desirable amount, as that figure was based on you having a couple of days of net gain, which is what you were implying to being with, that if you had days of net caloric gain, versus net burn, would it become a long term hindrance, so response was based on it not being a problem, as long as days of net gain were limited and the amount of net calories gained was not too much each time.
The 1,100 calorie a week figure was just an example, to illustrate the point.
Your BMR, (Basal Metabolic Rate), is the minimum amount of calories needed per day to sustain a healthy metabolism, so you could be wise to eat over that, by some way and then you can allow exercise to burn some of the added calories off.
You can, when you're having a couple of rest days, which would be advisable and preferably not back to back, reduce the calories slightly by 200-300 a day, to reflect the fact you're being sedentary.
I cannot tell you what an optimal calorie burn is per week, as most machines that monitor that are guides only. There is a way I can think of to test machines for similarities or differences, but it would involve something like this.
You use the same type of machine at the same time of day, several days in a row, but you use a different manufacturers machine each day and you'd need to be having the same diet and fluid intake on those days, and at the same times, so you were trying to maintain the same kind of nutrition, hydration and exercise conditions and the duration and intensity of the exercise would have to be replicated each time, so then the only difference would be the manufacturer not the type of machine or how it was used.
This could then allow you to see how different manufacturers ellipticals, or steppers or exercises bikes etc, registered calorie burn under the exact same conditions, to see if there was much similarity or broad variance, but you wouldn't be able to do this except under control conditions, as most gyms will have various cardio machines, but most of the time a particular machine they have more than one of, is made by the same company, not different companies, so you couldn't try what I outlined to test calorie burning monitors for similarities or differences.
Hopefully that's made things a bit clearer

.