It is less complicated than it looks, once the terms are clear.
Most people meet this once and never think about it again, which is exactly why it is worth reading up on.
What it costs
Most of the confusion comes from two terms that sound alike and mean different things. There is a deadline involved, and missing it costs more than the difference.
What to check first
The exceptions matter more than the rule, and there are three of them. The practical effect is easier to see in a single example than in a summary.
The exceptions
The practical effect is easier to see in a single example than in a summary. There is a deadline involved, and missing it costs more than the difference.
It rewards a little attention now and punishes leaving it to next year.