Wood is a natural element and has its own characters, which will have effects on staining and finishing.  Consistency of color is achievable only to certain levels.  Hand applications and custom staining techniques can and always will result in differences in the final product.  Humidity, due point, and other weather conditions all has effects on real wood with varying results on final product.  Overall, typically entire projects are usually consistent in color with the color varying depending on sunlight, daylight, evening, over-cast and mood lighting with reflective properties of adjoining walls flooring and ceilings.  This is to inform clients of the natural beauty of real wood.