When is Slow Cooking done - time vs temperature of meat I have read that slow cookers manufactured recently (not sure what time period that actually means) rise to their cooking temperature faster because of FDA concerns of keeping a food at a dangerous temperature for too long. The recommendation is to perhaps cook things for a bit less time than the typical 8 hours on low to avoid overcooking.

To this end, I have been putting a thermometer in my meat and cooking to a temperature instead of to any set time.  However, I'm finding the meat gets to its "done" temperature at WELL below the time suggested.  For example, I have a chicken recipe (skinless, boneless) that suggests cooking for 8 hours on low.  In my slow cooker, the chicken gets to 165 degrees at only 2-1/2 or 3 hours!  Well below the 8 hour suggested cooking time.

So, my question is, should I say my meal is done at that 165 degree mark, or is there any slow cooker advantage to leaving it in for the full or close to full cooking time?  It seems to me the meat just gets dry if I leave it in longer, but maybe if I left it in the full 7-8 hours, some other chemical process takes place, leaving the meat more moist and flavorful than if I take it out at the 3 hour mark because of the temperature.
The answer depends on the type of cut. If you have a tender cut of meat then there's no reason to cook it any longer than then desired doneness. If you are using a tough cut then there's lots of collagen that needs to be broken down, and that requires moisture and time. You want to cook it until all the collagen is broken down as that will make the meat tender. That may take 2 hours, it may take 6, it depends on the cut and the thickness. 

I have a similar experience with my slow cooker, it goes way too fast. To get around this I've ended up putting in big chunks of meat and veggies because anything else is completely nuked after 8 hours! I've also thought about using a light timer to have it start 3 hours after I leave home.