AMS 2750F pyrometric requirements: what changes for the equipment of heat treatment furnaces

Revision F of the AMS (Aerospace Material Specifications) 2750 introduces three important changes concerning the equipment of the instrumentation of the heat treatment furnaces.

Which are the changes to the uniformity requirements required by the technical specifications of the process and by the technical specifications of the material?
How are the types of instrumentation of heat treatment plants classified?
And finally, what is the new D+ instrumentation type?