Here's my thinking on the cost
In 2015 I bought a new 3/4 oz spin for the nationals.
I'll use it for at least one more national (2 year rotation)
In 2016 I would have to buy a new 1/2 oz. In 2017 a new 3/4 oz and in 2016 another new 1/2 oz., etc. If I go three years on the rotation, I still have to add one more sail to the inventory On a three year rotation net/net the cost is 2/3 of double.
Perhaps if you use "new math" the cost is the same. Hopefully someone can explain it to me
