When the bids for the two aircraft were submitted to the USAF in 2010 for the LAS program they were required to present a cost/schedule plan for obtaining a US military airworthiness certification (the A-29 already had a non-US certification). Ultimately the A-29 won because, according to the USAF, there was significant technical risk to the AT-6’s certification plan. Incidentally, this appears to be the same reason the Philippine Gov’t selected the A-29 over the AT-6. The USAF hasn’t procured any AT-6 aircraft. Does this help?
Fair enough. I read more into your comment than warranted.