Weight Watchers started calculating their dietary intakes using the Points system as part of their weight loss plans. In later years, they have extended the original Points system with "improved" computations of macro-nutrients. Basically they took a closer look at calories, and split it into two more factors.
No more muffins loaded with fiber to stay at 1 Point!
If you're still trying see how the "old Points" calculations may have worked, or just comparing numbers - the old Points system was simple.
Calories ~ Fat ~ Fiber = Points
*Calculator provides estimated points and may not be accurate, it is not an official Weight Watchers calculator.
The formula in use is an empirical match obtained from public sources.