Hotel Charlie,. .. .You're right, I am saying the same as N4641P - I'm just expressing it the opposite way to him (and the opposite way to the way it's usually expressed).. .. .I said: "in colder weather, the same actual altitude gives a higher indicated altitude.". .. .It's more usual to see this written as "in colder weather, the same indicated altitude gives a lower actual altitude.". .. .I suspect that it's because I reversed this statement from its more common form that N4641P thought I'd got it the wrong way around on his first reading.. .. .I'd still like to hear from someone who knows whether my explanation is correct or not!. .. .FFF. .---------