Generally speaking, disconnects are required to be Readily Accesible. Per Article 100 of the NEC, Readily accesible is "capable of being reached quickly for operation, renewal, or inspections without requiring those whom ready access is requisite to climb over or remove obstacles or to resort to portable ladders". See the respective article to the specific equipment that is requiring a disoconnect to see location specifications.
Disconnect for what purpose?
If a motor, you may have two disconnects, one has to be "readily accessible" and the other "accessible". See section 430.102 (A) and (B)
If Justo placed the disconnect at 6 1/2 ft. and the inspector says that wont do, is the interpretation of article 100 up to the AHJ or is there another way to settle the matter?
You may think this is a joke, but it is really true. One of the inspectors in my community is 6'5" and another is 5'3". They both definitely have a different interpretation of what is readily accesible. One doesn't like to have to bend over to look at equipment and the other is tired of stepping on his toes!