I just copied 9 files totalling 2.64gb and it took about ~19s, so that was an avg of almost 140MB/s .. much more in line with what I think I should always be seeing. So JDPTECHNC, you could be spot on with your assessment re: the number of files.
I always knew you'd get worse throughput with a higher number of files but I didn't expect it to be such a performance hit. I wonder if there is anyway to improve the copies now the slow down is ostensibly due to the number of files and not to the networking config.
Thanks again for the assistance JDPTECHNC!