Formula Help (Planned Duration & Estimated Date)

Thank you Evan. As I started typing answer to your question, I felt foolish. What a dumb question I have asked on Field 3. You are right, it is fixed # of days and I don't need a complex formula on Field 3. I will just make a form controlled number to show up on the field based on the selected "Template Type". Just advise me on Field 4. Thank you for pointing out the obvious.