Cooking a pot roast. Temp says it's fully cooked, but it's tough. Cook it longer?

thank you!

Yeah, lower the temp and simmer it a bit more.

I have a pot roast that has the same problem right now. Even while the 'cooked' temp is okay for 'safe zone' of cooked meat. A longer slower cook is often in order.

What will happen is that once the fat and tough bits hit their happy point (which has nothing to do with the safe point of being cooked)..when they get happy, it'll loosen up like you'd expect. This could take another hour two. IMHO...it's better the next day with another heating. After it's set in the pot overnight.
A lot depends on the cut of meat. I'd go 225 for another two hours. 200 is a bit low.

Potatoes and carrots should be added again for the second heating--as they'll just turn to mush for the long cooking. Good for thickening and flavoring the liquid. But an addition of fresh veggies for the second heat keeps those as individual elements.

Have you tried testing the bottom? Sometimes the bit that sticks out of the liquid gets tough, but the bottom part is tender. If you have the time, cooking it longer on low, may soften up the roast.