I have bought several liters from wizard labs, nude nicotine, and Nic River and they are all the same. I fill up my 8 oz bottles to the bottom of the neck. It takes four 8 oz bottles per liter with no extra. They have all been exactly the same.
But 8 oz. is 236.588 ml. So 4 of those is 946.352 ml, not 1000, which was my point.