Windchill Risk and Reliability - Environment Conversion

Is WRR supposed to automatically convert a "lower level" part Environment to the top most Modeled Environment (unless changed, all lower level items inherit the next higher assembly model...which I would assume the environment as well)?

This is real easy to test for EPRD parts:

1. Load a single part in an assembly with a stated environment of AUF.
2. Set the Top most assembly to Ground Fixed, and correct temp.
3. Calculate.
4. Same failure rate is summed to the top

The AUF part failure rate should be converted automatically for you when inserting an EPRD part...or at least that was my assumption. Otherwise, what's the benefit of being able to insert NPRD and EPRD parts? The tool provides a graph that allows one to graph failure rates over multiple environments and/or temp, so I'm assuming it has the typical conversion factors built into the tool.

Please help/explain.