Retirement tax questions

Thanks a lot for the detailed response dmertz. I really appreciate it.
-- Amount in box 2a. is zero.
-- I did provide detailed dates and corresponding statements to IRS.

There were couple of other items in the previous IRS letter. Now they closed them. This item is still left. I think they did not properly go thru my response for this item before. I will resend with detailed explanation and evidences etc. I hope they will close this as well.