We have some examples graphs here:

http://www.pingplotter.com/commonnetworkproblems/

And quite a few more scattered through the manual. The VoIP troubleshooting guide is also pretty good about talking through concepts with examples - you're not doing VoIP, but there the core concepts are similar:

http://www.pingplotter.com/manual/pro/voiptroubleshooting.html

PingPlotter, in its default configuration, sends out 56 bytes for each hop, and the responses are 56 bytes. Each request is separated by about 1/25th of a second, so the *most* bandwidth you can consume is about 1.4 KBps in each direction. This is not of consequence to most modern network connections, and barely a pebble in video streaming.

Online speed tests are built to saturate the network - they send as much as possible until the network is saturated. Doing bandwidth tests can be significantly disruptive to regular network operation. This is not at all the mode that PingPlotter works in - it tries to *NOT* use much bandwidth.

PingPlotter does not have the ability to distinguish between upload and download latency. It only measures the round-trip time (as you noted), there and back again. Incidentally, with a TCP connection (are you using TCP or UDP?), either direction being saturation will slow the other direction down, too, because the handshaking packets (error correction) will get caught up in congestion going the other direction.

- Pete