@ZSteve. Last try ...
Frankly I don't know what sense you are using "acceleration". Acceleration in the normal sense doesn't have anything essential to do with how much gas you have to give the car to maintain forward motion. Acceleration is not the amount of power you put to the tires to move the car forward. Acceleration is an *increase* in speed. If you accelerate up to a specific speed then if you maintain that speed -- say 65 -- you are no longer accelerating.
Did you read that wikipedia link?
From
Acceleration - Wikipedia, the free encyclopedia :
"In physics, and more specifically kinematics, acceleration is the change in velocity over time. Because velocity is a vector, it can change in two ways: a change in magnitude and/or a change in direction. In one dimension, i.e. a line, acceleration is the rate at which something speeds up."
There may be some word for what you describing, but it is not "acceleration" which has the specific meaning given above.
Perhaps you mean that since you can't really maintain an exact speed there is always a little bit of acceleration and deceleration going on. Or perhaps you mean that if the A/C shutoff were controlled by the voltage going into the ECU from the throttle it would be constantly shutting off whenever you give it some gas even if your speed remains constant. That's true, but it wouldn't be controlled by acceleration in that case. They could gate it by actual acceleration by rapidly sampling the MPH...
I agree with your overall point, but "acceleration" is not the phenomenon you are describing