Gail, I am not Ron but may I address your question....
The answer is that you have to keep to the exact timing of the recipe- the meat continues to cook when the oven is turned off and Ron's method needs to be followed pretty precisely in order for it to work- even though you turn the oven off and the meat cools down, the exact timing is still important.
Can I offer this very much T&T REC and method for you to try? I have made many, many roasts using it and it ALWAYS, 100% of the time, works perfectly if followed and may work better with your schedule. Don't be afraid. Make sure the roast is at room temp and follow the weight chart to a "t"- don't second-guess it. You do not need to put the potatoes in the pan- it does not change the roasting time. Good luck and don't be scared- this is an AMAZING recipe.
STANDING RIB ROAST (serves 4-8. Each rib serves 2)
Ann Seranne from the Best of Craig Claiborne
2-4 rib standing rib roast (4-1/2- 12 lbs), short ribs removed
all-purpose flour
salt and freshly ground pepper
3” red potatoes, pricked and tossed in oil
1/2-1 cup beef broth
Remove the roast from the refrigerator 2-4 hours before roasting, preheat oven to 500 degrees. Put the roast in a pan fat side up and rub some flour into the fat. Sprinkle with salt and pepper and place the potatoes in the pan around the roast. Put the roast in the oven and bake according to the chart below. When the cooking time is up, turn off the oven and do not open the door. Leave it in the oven until the oven is lukewarm, two hours. If you need to use the oven for something else, remove the roast and tent with foil. To make a thin gravy, remove the excess fat from the meat drippings and stir in the beef broth. Bring to a boil, scraping the bottom of the pan to loosen the meat pieces. Simmer for 1 minute and season to taste.
Roasting Chart (thanks to a friend who is an engineer and good with calculations):
LB Minutes LB Minutes LB Minutes
4.00 25.26 6.25 39.47 8.25 52.11
4.25 26.84 6.50 41.05 8.50 53.68
4.50 28.42 6.75 42.63 8.75 55.26
4.75 30.00 7.00 44.21 9.00 56.84
5.00 31.58 7.25 45.79 9.25 58.42
5.25 33.16 7.50 47.37 9.50 60.00
5.50 34.74 7.75 48.95 9.75 61.58
5.75 36.32 8.00 50.53 10.00 63.16
6.00 37.89