This is a withdrawn posting.
Is the reward 10% or 20%?
Broadly speaking, the Founder's Reward is 10% of the projected total supply of 21 million ZEC. To achieve this, the founders are allocated 20% of the first 10.5 million ZEC minted.
Edit: Ah, you beat me to it GPU_Mining!
So it's 20% of the block reward (you should stop 'deliberately' confusing people).
Projects need to be funded so I support a 'way' of ensuring that this is done, would've been happier with 10% though.
The Total Coin Supply is a different topic altogether, and of course your calculations there are correct.
Actually it would be accurate to say 10% of the total or 20% of the first 4 years.
From now until the 4 year mark the Founders will possess 20% of all of mined ZEC. Only after that point will the Founders percentage slowly dilute down to 10% during the remaining mining lifespan, which will take many years.