I am saying the gravitational effect on an atomic clock is the measured and predicted gravitational time dilation.
http://en.wikipedia.org/wiki/Time_dilation#Gravitational_time_dilation
"Gravitational time dilation There is another case of time dilation, where both observers are differently situated in their distance from a significant gravitational mass, such as (for terrestrial observers) the Earth or the Sun. One may suppose for simplicity that the observers are at relative rest (which is not the case of two observers both rotating with the Earth—an extra factor described below). In the simplified case, the general theory of relativity describes how, for both observers, the clock that is closer to the gravitational mass, i.e. deeper in its "gravity well", appears to go slower than the clock that is more distant from the mass (or higher in altitude away from the center of the gravitational mass). That does not mean that the two observers fully agree: each still makes the local clock to be correct; the observer more distant from the mass (higher in altitude) measures the other clock (closer to the mass, lower in altitude) to be slower than the local correct rate, and the observer situated closer to the mass (lower in altitude) measures the other clock (farther from the mass, higher in altitude) to be faster than the local correct rate. They agree at least that the clock nearer the mass is slower in rate and on the ratio of the difference."
The only reason for each observer to make the local clock to be correct is because they are unable or unwilling to understand the rate at which an atomic clock ticks is determined by the physical state of the space in which it exists.
If you own a battery operated clock and it ticks slower has time changed or do you replace the batteries? You replace the batteries because you understand what occurred physically in nature to cause the battery operated clock to tick slower. Now, you may say an atomic clock is more accurate than a battery operated clock. The Earth orbiting the Sun clock is more accurate than an atomic clock.
As I am going to be banned. This is my last post.