In Oregon a test is taken from every 10 pounds grown. So if you grow 100 pounds you need 10 tests... in Nevada it is every 5 pound.
I thought i read it was per pound in Cali, but i could be wrong... Have to search for the info...
Its also important to understand that some of these smaller companies might not have this many pounds of one strain and will have to get tests for each strain as well.
My postings contain many opinions. So please do your own research and validation.