While I was testing a PTP link with a couple of Cisco 3702E, I noticed a not very common data rate, at least different than we are used to see with the normal MCS index. 

After doing to research and reaching out a couple of friends about it, I finally found how to interpret it, it happens to be a 802.11ac data rate, one that cisco uses now, at least in autnomous APs.

https://supportforums.cisco.com/document/11938046/how-interpret-80211ac-datarates

Thank you for reading!