Why is my upload speed cut in half within a week?

I got hired by this work at home company call Cloud 10 and you computer has to meet the minimal requirements like pass a battery of test. Last week I checked my download and upload speed on a utility that Cloud 10 prefers you to use called PC Pit stop. Last week everything checked out OK. My download speed was 10.98Mbps and my upload speed was 1.05Mbps which passes the minimum requirements. The HR representative wants me to retest my computer and email her the results and now my upload speed has dropped to 0.45Mbps and that is way below the requirements. I've ran all types of checks from registry errors to malware checks and nothing fixes it. I call my ISP and they sent a tech to look at the problem to see if it was the modem and it wasn't because he plugged his computer to my line and everything checked out on his computer. Am I missing something because this is getting very irritating and could cost me a good job in the process.