Google “NDC and American Airlines” and you will see the reason for the fare differences.

MR are used for most of our corporate travel. The implementation of NDC has cost AA about $30k in revenue from my small business. Most of that revenue has gone to DL.

I believe I read the threshold to release inventory to OTA is $170 one way for coach. Based in ATL, most flights to AA cities fall under the threshold. I have read that AA is feeling the loss of revenue and may adjust NDC parameters.

United does very similar things with NDC.