Um... you may have misunderstood the developers but at the moment a price of 10 dollars is being considered. It will be 30 Dollars if you don't already own Hegemony: PoM, but if you do own Hegemony: PoM (as you do) then you can upgrade to Hegemony Gold when it is released for a special price, the aforementioned 10 dollars. Quite a good deal really in my opinion, all in all get Hegemony:PoM and Hegemony Gold for something like 12 dollars (forgot what price it sold for on Steam that day). Maybe you disagree, which is fine, but someone has to help fund new projects.
If you own Hegemony: Philip of Macedon you can upgrade to Hegemony Gold at release for 10 dollars (subject to change).
If you do not own Hegemony: Philip of Macedon then Hegemony Gold will cost 30 dollars (subject to change)