Its not more abundant, the percentage are just the resonant frequencies. When it is charted, it shows the total element. Copper has a different resonance than Chromium. I have not located the old printouts yet, but an example is the picture attached to this response. This is a sample of paint. But it is the total resonance of all together that tells you the color or make-up of the paint. You see, the radiation causes the elements to Vibrate like the crystal in the radio, this vibration is rebounded back to the sensor as a reading based on intensity. When taken together, you can then chart and compare to a like source to determine the actual Color, or chemical total makeup. This is an example below from paint. In this way, if you take out the metals contents, then what you have left is the basic finish. And since steel is not processed with Copper, then the copper has to be in the finish. And when copper ages or reacts with other metals, the color usually turns out green expecialy when exposed to Sunlight, Acids, or solvents like what is used in finishing steel.