I don't know why you think that 1 ::goldore:: would produce 1 ::gold:: and 1 ::gold:: would produce 1 ::coins::.
If you look at the details tab of the coinage (when it isn't buffed) you see it requires 4 ::gold:: for 1 ::coins::.
If you look at the details of the gold smelter (also not buffed) you see it requires 2 ::goldore:: for 1 ::gold::.
So you need 8 ::goldore:: to produce 1 ::coins::.
If you buff with ::giftbasket:: (Aunt Irma's Basket) your output multiplies with 2, so that would make:
4 ::gold:: for 2 ::coins::
2 ::goldore:: for 2 ::gold::
So you need 4 ::goldore:: to create 2 ::coins::
