Netmetal RB921-UAGS 5HPac low bandwidth on NV2 and Nstreme

Hello Support Team,

Recently we tested out Netmetal RB921-UAGS on 20 Kms. getting signal of -60/-63 dBm with 27 dBi Dish. Here are some observations

Band 802.11 a/n/ac
Channel Width : 20/40/80
Wireless Protocol (ANY) : UDP throughput 140 Mbps Transmit and 80 Mbps Recieve.
TCP 20 Mbps Transmit and 8 Mbps Receive

Wireless Protocol (NV2/Nstreme) : Link is flapping/High Latency

Band 802.11 only AC : High Latency/Drops in Wireless
Channel Width 20/40/80 (all)

Can you please tell why NV2/Nstreme and TCP bandwidth test decreases the performance of wireless.

ROUTER OS version 6.27