Putting must have changed because FAST is now the zero speed. So a 20ft putt on a flat FAST green is a 20ft hit. On a STANDARD green its +10% so a 22ft hit. VERY FAST would be -10% so a 18ft hit. TOURNAMENT (12) speed is -30%. CHAMPIONSHIP -40%. These are to get the ball to stop close if you miss.
If you have a putt that is uphill more than 5 inches you need to take 10% off these numbers. So a 50ft putt that is 10 inches uphill on a FAST green would be 50 + 10 = 60 - 10%(6) = 54. On a STANDARD you would just hit it 60ft as the extra 10% hit cancels out the -10% for uphill. Downhill doesn't have any extra calculation except for TOURNAMENT and CHAMPIONSHIP greens. There are many variables and some courses are quicker than others but this should get you close to the hole if not in.