Yes, after looking at the graph and axis more closely and getting clarification from helpful posts on the forum, I realise that.
I am sure you are correct, no-one could possibly ever, conceivably, on a glance, misunderstand what that graph was depicting.
I mean, I do not know how someone would dare ask for clarification or help on something so simple. I cannot believe that anybody could/would/should waste their time with such a person. That idividual should be publically shamed ,their error made clear for all to see. Exposed for the faud that they are! God forbid they ever looked at a graph again for fear of the repercussions!
Every time that person took step into the bathroom they should feel appalled that for a brief period, they thought that their extractor fan had a variable m3/hr extraction rate over time!! Their tears of ineptitude would be drowned out by the water from the shower, as they watched the steam get sucked into the extractor, which was indeed extracting air at an m3/hr rate in relation to the resistance of the length of ducting.
"The fool!" they would cry, but alas, their voice would lost against the whirr of the centrifugal fan.