If I can add to this, I'd suggest that you also realize that there just may be more utilization in one direction than the other which of course will lower session performance in some cases.
When testing, be sure to disconnect the LAN at both ends and test from notebook to notebook to rule out the network as a possible issue. Once the WAN is proved clean, you can focus on what on the LAN is utilizing the bandwidth.
Hope this helps.
Fred
