Thanks for that CJ Driver.
What you say makes sense really when you consider that a symmetrical airfoil at O degrees has a symmetrical reduction in pressure on both the upper and lower surfaces and as you say, at typical angle of attack at cruise speed would make for a low angle of attack.
The annoying thing is, I have checked the reference that I have (Aerodynamics for Naval Aviators. ISBN 0-89100-370-3) and it depicts Airfoil Pressure Distribution three times with diagrams.
The first on page 17 indicates both higher and lower pressure than ambient on the lower surface of the wing (the higher pressure along the forward half and the lower pressure along the rear half.)
The second one on page 19 clearly indicates higher than ambient pressure along the entire lower surface of the wing.
And on page 48 it indicates lower than ambient pressure on both the upper and lower surfaces with what you describe, that is that the pressure reduces more on the upper surface than it does on the lower surface.
No wonder there is confusion about this.
Anyway I don't want to change the subject. TAT vs fuel temperature. It's an interesting discussion.