Testing MPTCP on LEDE

I have two TP-Link Routers running LEDE with MP-TCP kernel version 4.4.70. One of the routers runs as an AP and the other runs as a station. I use the two wireless interfaces 60 GHz and 2.4 GHz to establish either a single TCP flow or two concurrent flows using MP-TCP. I generate traffic using iPerf v2.0.9. When I use the 60 GHz alone (802.11ad), I get 1.85 GHz of throughput. Whereas when I use the 2.4 GHz (802.11n) alone I get 20 Mbps. The strange thing is when I use MP-TCP (i.e. two flows at the same time), I get around 300 Mbps. So why am I getting this strange result? Should not MP-TCP achieves throughout of 1850 Mbps + 20 Mbps. I tried to tune TCP parameters like maximum read/write buffer but with no success. Here is the network configuration: **60 GHz Interface:** IP Address: 11.0.0.0/24 **2.5 GHz Interface:** IP Address: 10.0.0.0/24 **MP-TCP Configuration:** Congestion Control: Cubic MP-TCP Enabled: True MP-TCP Checksum: False MP-TCP Path Manager = Full Mesh MP-TCP scheduler = default MP-TCP syn retries = 3 MP-TCP version = 0