I am also wondering about this, since I have never gotten Repo Speed Test to do anything but report failures. I tried changing the sync delay from 5 days (all repos fail at this setting) to 3 days (all fail), 2 days (all fail), but at 10 days, only pclosusers.com is successful (all others fail). It doesn't matter what time of day I attempt to run Repo Speed Test.
Obviously, I'm connected to the 'net (I'm typing from the same computer that reports all the failures). Nothing I do will make Repo Speed Test work. Does it not like wifi connections? That's the only thing I haven't tried.