I unwisely bought 2 gallons of satin paint, light base, light grey/blue. I should have gotten a sample. I hate the color. So I took the paint back to see if they could grey it up more. They did, but could only go so far since it was light base. While there I bought a dark grey med. base gallon of flat paint on the discount shelf. If I mix the 2 gallons of satin with the 1 gallon of flat, what problems will I encounter?