Louisa,

You may be good at commentary, but I am great at talking non stop! Sadly this doesn't mean I always know what I am taking about!

The 10-12x rule is times your current weight, so yes, you will always be adjusting it.

For you sister, I think she would be full long before she reached those numbers! All she should worry about for now is just counting the carbs. The times your weight rule helps those who seem to be stalling out, or not losing as fast as they want. But not everyone has to worry about it.