It is less complicated than it looks, once the terms are clear.
The change has been coming for a while, but it only became obvious this year.
What it costs
The figures move about, but the direction has been the same for three years. The practical effect is easier to see in a single example than in a summary.
The exceptions
The figures move about, but the direction has been the same for three years. The practical effect is easier to see in a single example than in a summary.
Where the confusion starts
The figures move about, but the direction has been the same for three years. There is a deadline involved, and missing it costs more than the difference.
None of this is urgent, but it is worth an hour before the next renewal.