I found HTMA to be too infrequent to be useful. If you are very good at interpreting the analysis it may reveal high copper at the time of the test but this only represents a long term trend. Since starting methylation/thyroid/oxalate protocols I've actually swung many times from copper toxicity to frank, full blown deficiency within the same few weeks.
I think this is what Fredd refers to as functional deficiency vs. overall body deficiency. I also think that at certain times I'm dumping old toxic copper with other things. My latest thinking is that this is related to oxalate deposits which trap copper, aluminum, cadmium etc. Since I've been doing oxalate detox I've had a few cycles of heavy aluminum dumping cycling with copper dumping but oxalates will also strip copper from the body so at other times I have been deficient. I have no test to show this. I go by how I react to certain supplements and toxicity/deficiency symptoms.