Click on Average, Maximum, and Minimum any time after the test to dispay that throughput for the last completed test.  Also, the selection that you are currently on,

will be the one that will be displayed and logged for the next test.

Average Throughput

Average throughput is 'Total Packets' or 'Total Streams' multiplied by 'Packet Size' and then divided by 'Time to Complete' for the complete test.

Maximum/Minumum Throughput

Maximum and minimum throughputs are the maximim and minumum speeds for all packets in that test.  In other words, lap timers keep track of fastest and slowest packets written and read during the duration of the test.  

Please note...  If you're only testing with 1 packet, then average, maximum, and minimum throughputs will all be the same.