Thanks to friends, I've finally gotten some Jetta (maybe Golf) TDI, mph vs MPG data and updated this graph:
I'll attach my spreadsheet so folks will have the data but here is how I see it.
MPG at 75 mph is the key data point. Cars that get better than 40 MPG at 75 mph will do well in the EPA, Euro and automotive press. But if their highway mileage is under 40 MPG, they will be reported as 'dogs.' Notice that my NHW11 fits in that category but the reason for my lifetime 52+ MPG is extensive used of 65 mph as my highway speed limit. But the EPA thinks it is a 41 MPG highway car. Knowing where the 'knee in the curve is,' allows an informed driver to trade off: good, fast and cheap.
Bob Wilson