I can confirm it. It's what's called the International Standard Atmospheres lapse rate (ISA LR). And you are right, it is 2 degrees C per 1000 feet. This is very useful in estimating freezing levels.
What the lapse rate (LR) is is actually a measure of atmospheric stability.
The actual lapse rate varies from airmass to airmass, and is determined by this formula:
LR=Temp(bottom)-Temp(top)/Thickness of layer
When you compare it to the Dry Adiabatic Lapse Rate (DALR), you can tell how stable or unstable the airmass is. The DALR is a constant 3 degrees C per 1000 ft.
LR > DALR = Unstable atmosphere
LR = DALR = Nuetral atmosphere
LR < DALR = Stable
We can get into why this is if you want, but it's sort of outside the scope of the original question.
Remember one thing though: Temperature and Dewpoint don't converge at the ISA LR. They have their own. It's 2.4 degrees C per 1000 feet. This is very useful in estimating cloud bases.
And regarding the term "temperature deviation," I've never heard it before, and I can't find it in the glossaries of my weather books. But, in answer to your question, it's really quite important to know about the temperature. It goes into computing, well a lot of critical information, such as takeoff/landing distance, density altitude, true airspeed, and the list goes on.
Hope this helps. Fire away if you need me to clear anything up.