If you have more hops on nv2, and you do the tests using speedtest(your customer, speedtest make one tcp connection) or using btest(one direction, tcp, 1 connection), your throughoutput will be max 15mbit/s.
But when you create more tcp connections(20 - default), your throughoutput will be in my case 50mbit/s.
Why is this like this? (I do the same on ubnt link, and there was: with 20 tcp: 45mbit, 1 tcp: 38mbit).
This can be bad, when your customer have paid for higher speeds....and test it using one connection...