I noticed no difference in the two flow tests.  That is not a bad thing, just
that this test doesn't hit that code.

The anomaly is that first flow does slow start then gets loss and ends up
reducing it's window size all the way to the bottom, finally it recovers.
This happens with Cubic, H-TCP and others as well; if the queue in the
network is large enough, they don't handle the initial loss well.

See the graph.