Thanks for writing in - and thanks for trying out PingPlotter!
When you say that you're seeing packet loss "across the board" - the one thing you want to look into (and what Comcast *may* be referring to when they're asking you to "dig down") is to see if the packet loss you're seeing at earlier hops in your route is actually affecting your final target. Some devices simply don't prioritize ICMP requests very high (or don't respond to them at all). We cover this topic in quite a bit more detail here, if you're interested:http://www.pingman.com/kb/5
When you see packet loss at your final destination, you want to go back up through your route to see at which hop that pattern of packet loss starts. This is most easily accomplished by making use of PingPlotter's timeline graphs. We've got a guide that goes through some best practices and strategies for this, which you can find here:http://www.pingplotter.com/gsg/findproblem_intro.html
We've also got a great step-by-step guide that goes over the entire process of troubleshooting a network problem using PingPlotter, which may prove helpful to you as well:http://www.pingplotter.com/netnirvana/
It's a bit tough to try and speculate or diagnose any issues based off of the limited information we have from only your screenshots here. If you'd like, feel free to send over any .pp2 files you may have collected (in Pingplotter, "File" -> "Save Sample Set"), and we'd be happy to take a look and offer some more specific guidance from there.
Hopefully this helps to get you headed in the right direction. If you should find yourself with any questions, or needing any additional assistance - please don't hesitate to let us know!