Guessing on the CI qualification tests is not encouraged, at least not the way it is done in the US. These tests are to find out what you actually understand, not how well you have learned to cope with your hearing loss. If a sentence is "The river was high because of the rain" and you heard "river, high, rain" that is 38% of the words. If you add in "The, because, of, the", that is now 89%, even though you just guessed at what those words were and did not really understand them. The tone test is not part of the actual CI qualifications in the US but it is used as a baseline to see if it is worth testing for CI's. The CI testing is different then the HA testing.