Download and Upload Speed Discrepancy

I purchase premier internet service from Cox; as a consequence, I expect a download speed of about 100 Mbps. A few minutes ago I ran a speed test using a test provided on the Cox website. Download speed was reported to be 95 Mbps; upload speed was reported to be 15 Mbps. That would appear to be good enough, and not worth quibbling about, but I then ran a speed test using a test provided on-line by the Geek Squad. The Geek Squad tester reported a download speed of 30.38 Mbps and an upload speed of 23.44 Mbps. Frankly, I'm prone to trust the Geek Squad test since they're not affiliated with any ISP, and would have no reason that I know of to report biased results. My experience tells me that self-tests and self-evaluations are so unreliable and biased, I wonder why anyone bothers. I suggest Cox employ a truly independent tester to provide speed tests via their website, and advertise that they are truly independent. I'd be interested in seeing your comments on the subject.

I've begun to look into this matter because Cox download speeds have been very erratic for the past few months, especially during the day. For example, on-demand movies offered by DIRECT-TV often won't play, because they pause to buffer, because the Cox internet download speed is too slow; and a member of my household gets rather understandably anxious when the internet speed slows to a crawl while taking a timed, on-line, college exam.