I've pondered something similar,... regarding the calorie limits of the SLD
Here's what I came up with:
1. There's a saying, too much of a good thing can end up being bad. So if we go by that, then we acknowledge that there IS a point where increasing SLD calories is less worthit.
2. I messed around with a concept of how let's say you consume 500 calories of flavorless oil per day, it winds up being as effective as having a 500 calorie deficit per day, as if you were regularly dieting via calorie restriction. 500 calories per day of deficit leads to expected weight loss of 1 lbs per week.
I arrived at that idea by the following logic: If you consume 500 calories per day with 0 increase in your setpoint, your body is being fed the fuel worth 500 calories and so "closes shop" and tells you that you're done eating for the day, 500 calories earlier than you normally would. This then winds up with you having a food caused set-point raise that's 500 calories less than it would normally be. So in EFFECT, it could be as if you daily ate 500 calories less. Its how your set point would go each day.
3. Human beings have social eating norms. This usually includes at least 1 meal per day, and most meals have at least 500 calories in them, usually more. If let's say you upped the SLD calories to 1000 calories per day, according to your new setpoint, you might probably do best if you only consumed 500 real food calories per day. However, this isnt practical and while in theory it would cause you to lose weight even faster, it will mess with your mental concepts of dieting, social behaviour, and overall be a bit too much of a hassle.
4. Most diet authors have mentioned that it is usually best to AIM for weight loss within the range of 1-3 lbs per week and no more. The reason being that higher rates almost always result in the loss coming from water and lean mass.
So when you think of all that together, it makes sense to stick to 500 calories per day or less. This has minimal interference to preferred eating patterns and doesnt try to overdo the fat loss rate, which then has a strong possibility of backfiring, via lean mass loss.