When using a wiping stain, there are a few things that you should keep in mind. Letting the wiping stain sit for 45 seconds is ideal, but that depends on the temperature when it is being applied.
When the stain sits for 45 seconds it has a chance to absorb into the fibers of the wood and penetrate to give it a full color. This is achieved by removing the excess stain with a cotton stain rag or pad. A uniform color should be seen very easily when the wiping stain is applied correctly and is allowed to sit for 45 seconds. As everything else in the finishing business, the type of wood will vary the process in which the stain is applied. For instance, hard maple is a much harder wood and might require more time for the wiping stain to absorb into the wood.
If the wiping stain is not allowed to sit for 45 seconds, it is possible for inconsistent color and an unhappy end result. It is also possible for the wiping stain to sit for too long too. You need to make sure it does not sit for too long, otherwise it will become very sticky and hard to remove.