T levels

At the beginning of 2012 when my derm prescribed blood test for me he checked for free T and not total T, I don't know why. the question is at that time I was already on fin for a long time (5 years or so) so I was expecting to see high levels of T. The range was 5.1-41.5 and my result was 21.33 so it is pretty in the middle, not low not high. So I wondered if fin was really working for me or not, I don't suppose 21.33 would be my elevated level? I haven't taken any tests after starting dut, but I am bit concerned since dut blocks more DHT there will be more testo, and how high is too high?