I have read the other threads and understand that the fresher the bean the better. Also that the closer to brew the better. This question directly relates to the use of a morning cup that is brewed with a timer set drip maker in which the grind takes place the night before. Can someone truly taste the difference between a grind done 8 hours before a brew vs 12 hours before a brew? Will that 4 hours truly make a difference in the chemical composition in a perceptible fashion after it has already been sitting for 8?
While the timeframe between grind and brew affect the taste of the coffee I wouldn't go as far as measuring it down to hours. Of course it is best to grind directly before brewing, but in your case, as you use a timed drip maker I don't think it acutally does make that of a difference.
Plus other aspects also affect the flavor of your coffee (water temperature, temperature of surroundings (kitchen), way of extraction (in your case it could be the way the grounds sit in filter) and, for a great deal, the age of the coffee itself. So if you taste a difference, it could be the result of (an)other factor(s) as well. Not only the + 4 hours of 'sitting time' the grounds had.
To sum it up: Simply try it yourself (as Pete Becker mentioned in the comment).
It's sort of an exponential thing (well, logarithmic actually). There is a big difference in smell between, say fresh ground to four hours, but less of a difference between 4 to 8, and even less at 8 to 12. When it's first ground, much of the aroma evaporates into the air, so there is less to lose hours or days later.
If you have the luxury to grind the coffee right before you brew, then go for it. If you're trying to plan your day, though, so you can brew in 8 hours instead of 12, I'd say it's not really worth the extra effort. Grind it, put it in an airtight (mason) jar in the freezer, and you'll be fine for a week or so.
Much of taste is down to smell, if you cannot smell a difference in coffee that was ground 8 hours versus 12 hours before I doubt you would taste a difference. It would be an interesting experiment, if you try it let us know the results.