Hi Timothy,
The threshold is less than 60% of advertised speed. After troubleshooting has been performed. If we see a consistent slow results, and not much change in customer experience, then we always work with our engineers to make direct changes to customer sites. We've seen tremendous success with in here on the community. It can however take some time depending on the situation. That along with our other community members insight has increased our success rate. Hope this answers your question.
Thanks,
Chris