The technical explanation on why packets received are more than packets sent is as follows

1. This is being measured as part of our UDP protocol metrics in layer 4 in the source and in the destination

2. Let us say UDP protocol at source node A sends a datagram. At the MAC - WLAN send the frame and starts a re-transmission timer. 

3. If not Ack is received within this timer period it would initiate a re-transmission (consider cases where the WLAN Ack has a collision or is errored)

4. As the destination the MAC (WLAN) layer would send up to UDP both the first packet it received and the re-transmitted packet it received. 

5. UDP protocol in the destination would count both the packets received