Ocenus ,you seem to have very good experience in FDD and TDD and you micht have involved in preparing FDD and TDD as Tech lead. I would love to prepare FDD if Architectural Design Document and the Infrastructure Impact Assessment are written in way it is supposed to be.It is not hard to generate FDD if you have well defined Functional Requirement Document.FDD should provide clear picture of high level and low level requirements. I think,TDD is prepared by a team of Data architect,developer and tech lead in most of company and role of BSA is just to validate transformation of FDD to TDD.(may be a few company have different approach to it) Could you please share your experience in FDD and TDD?