As we have advised, wood can be difficult to work with in that you will not always achieve the results you were looking for. So, even if you follow the same method on all of your wooden planks, there is a strong likelihood that the planks will be different in color - it just is what it is. When aging wood, the majority of people are looking to achieve a mixed-color look. if you are working with darker wood and have darker and lighter planks, you can slightly sand down the darker planks to lighten them slightly. Another option is to reapply your solution to make the wood lighter or darker as required. If you think of an old tool shed or barn, the planks of the wood are never all the same color; the result of years of exposure to the elements has weathered each piece of wood differently, and this is the same effect you will achieve.