The analysis bar chart will show the value for each bar if you hover the mouse over the bar, the download test latency should only be a couple of times higher than the idle latency.

On the other testers, without access to your network card monitoring (Windows 10 does this in Task Manager) impossible to say if they are reflecting reality or not, or the way they handle traffic is getting around this problem.

BT Wholesale test - please just ignore it.

The key thing is how is the connection behaving in day to day use?

Also how do the devices behave when using other connections that are otherwise known to behave well.