Can you use Revlon Color Silk if you just shampooed 5 hours ago?

the box says ';Do not shampoo immediately before coloring. If hair is very soiled or has heavy build up of styling aids, shampoo 24 hours b4 application'; does that mean I only have to wait 24 hours if my hair was yucky, or can i color it now?Can you use Revlon Color Silk if you just shampooed 5 hours ago?
It is best to color your hair when it is ';dirty'; or when it hasn't been shampooed for a while.. The color holds better. You wash your hair when your done coloring, so its not like your hair will stay ';dirty';