Hello, to expand on what Anthony is saying, when a beam is created to the intended SM, additional beams are created about 50 degrees off of the original azimuth (by nature of how the RF elements are energized). A zero azimuth is dead center, so you will see three angles for the first 5-6 spatial frequencies (-50, 0 and +50 degrees). Once you get past ~7 degrees, the third beam goes outside of the range of the antenna and only two beams come into play. From the AP's perspective, if the SMs are within either of those beams, the AP considers them as one (multiple TDD cycles would be needed to service them).
These values are SNMP pollable, so you may be able to take this information and overlay it on Google Earth to get an idea of where you can add users to AP and actually increase the overall sector performance (or where you don't want to focus anymore). The simple end goal for an operator would be to evenly distribute your customers across all of the spatial frequencies (versus clump them all into a few). That will give you the maximum spatial multiplexing gain (average number of beams per TDD cycle).
http://community.cambiumnetworks.com/t5/PMP-450/15-1-1-450m-Additional-MU-MIMO-statistics/m-p/76417