The other thing that just occurred to me:
In the "meat" (beef and pork, as opposed to poultry) category there are really two different types:
tender and not tender
Tender - Rib roast, filet, pork loin, etc
Not tender - brisket, chuck, pork shoulder(butt), etc
The tender cuts you are going to take to a "traditional" doneness IT - like 130 for medium rare for example.
The non tender cuts have various amounts of connective tissue(mostly collagen) that will need a low and slow treatment to be broken down into gelatin and water. These are the ones that you cook longer and to the higher IT - 190-200F for pork butt/beef brisket.