I have a question on two terms used in defining a new thread.

Thread Minor Diameter and Thread Minor Diameter Inside

The data for a 1/4-20 from the hole wizard data:

       Thread Minor Diameter;  = 0.1905
       Thread Minor Diameter Inside = 0.1959

I can not find any thread data close to the numbers given above for a internal thread in any of our thread data books.
Is the Thread Minor Diameter the theoretical diameter for 100% full thread?
I just need to know exactly how the terms above relate to physical thread geometry.
And where I can find the data or what formulas are used to derive them.

The answer in S-04970: Thread Minor Diameter = the diameter of a cylinder formed by the roots of the threads
                                        Thread Minor Diameter Inside = the diameter of a cylinder formed by the crests of an internal thread
Is unclear at best as to how the number relate to the actual thread geometry.

Even my VAR can not give me a clear answer as to exactly what Thread Minor Diameter and Thread Minor Diameter Inside are.