Ping Plotter Question

[Chaiyoabc]

When monitoring the PP’s graph, what determines lowering or raising qos percentage when there is spike in graph?
 

For example, like when I see spike in graph, should I lower or raise percentage? 
 

ps. I always saturate bandwidth by having 4k youtube video and 200gb test file download in background

[Netduma Fraser]

Generally you should always be lowering the percentages to get better results, it's unlikely you'll get great results at a high value like 95% for example.