You could do that but i don?t think it would be very effective. I believe i read somewhere that redosing codeine before it wears off is generally ineffective because the liver enzymes that metabolize it to morphine are too occupied by the metabolites to effectively/efficiently convert codeine to morphine. I could be completely wrong on that though.
The other reason i think it wouldn?t be very effective is because once you have pretty much any drug active in your body it blunts the effects of the next dose. That?s not to say it doesn?t have a stacking physiological effects like increased CNS depression, rather the high is blunted. Also this kind of redosing will increase tolerance more then just waiting until the next day or until the dose wears off, at least in my experience.