So I finally figured it out (for anyone that cares)......
MAKE SURE YOU BUILD YOUR ENTIRE REPORT BEFORE YOU ADD IN THE FILTERING FUNCTIONALITY TO BE ABLE TO INPUT A CLIENT NAME
Yes, that's right. When you create the report, DO NOT define your filter before you get it exactly how you want the report (which can be an adventure in itself, and caused me to spawn two or three more bug reports.....).
Once you get the report fields just right, edit the report, go into "Filters", select the context and time window however you want to configure them, and then under "Define Filter", for the "Field" option choose what field you want to filter on (in my case the client name) and check the "Specify value when report is run" check box immediately below the "Value" input box. This will clear the "Operator" and "Value" input areas. Select the double right arrows along the right-hand edge of the "Define Filter" area to move your filter definition into the "Filter Definition" area, define how you want your results shown, hit finish, and you're all done!
But, like I said, editing the report after this step is sometimes impossible as everything that you would normally edit just shows up as a blank screen. I was able to reproduce the results in my more detailed report I was trying to create, but on a smaller test report, everything came back how it should have.....so you're taking your risks on being able to edit the report in the future without deleting it and recreating it (which I did for my bigger one about 30 times over the last 2 days).
Hopefully anyone else with some interesting input will post their findings here, and if anyone would like exports of the reports I've built (only have two worth anything right now), feel free to contact me.