Somebody will correct me if my recollection on this is incorrect, but from memory, the tranformation matrix returned from this function (like the LISP nentsel) is a compound matrix. This means that if you picked an entity inside a block reference, which in turn was inside another block reference, it's the resultant matrix of the 2 block ref transforms.
Bryco, can you give me more detail about what you are trying to do and the results you have thus far and I will try and look at this tomorrow.
Cheers,
Glenn.