Problem with a range is you can't weight it. On 85-100 you have an equally high change of getting 85, 86, ... , 100. The idea with dice is you can weight outliers. On 3D6, you're most likely to get the numbers in the middle than a "3" or a "6". If you want a number in a range, you'll have to do 1D50, then on another page add 50. That would give you a range of 50 to 100.
