This model encourages teams to have riders in all categories and rewards riding ability appropriately.
The rationale for multiplying different categories by 4, 2, or 1 is for the same reasons that we have more prize money for higher categories -- rewarding hard work/riding ability with more points. Winning the 1/2 race is a greater accomplishment than winning the 4/5 race. The multiplication factors also discourage sandbagging.
Additionally, should a team that has lots of 4's and a few 2's be on equal footing with a team with lots of 1/2's and a few 4's?
In the NCCA, they have used a similar model as this with a great deal of success. Their model encourages riding at an appropriate category and also encourages higher category riders to help and recruit lower category riders.
Dave
cyclingutah.com