If they get a lab result that is over 1%, that is all they get - "element is in excess of 1%." It does not say that it is 20%. It is like plugging a voltmeter into a wall where the range of the voltmeter is 100 volts AC. The needle will peg to the right, telling you that you have more than 100 volts. Could be 110, or it could be 220. So, you set the range on the meter to the next higher level and retest.

This is the same for chrome. If it is over 1%, you need to send it for a different test to find out if it is 20% or 50%.