What the numbers actually say, once the headlines are set aside.
It is the sort of thing that seems settled until you look at the detail.
The exceptions
The exceptions matter more than the rule, and there are three of them. Most of the confusion comes from two terms that sound alike and mean different things.
What it costs
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.
Where to go from here
Nobody is required to explain this to you, which is half the problem. Most of the confusion comes from two terms that sound alike and mean different things.
Whatever you decide, write down why. The reasoning is the part you forget.