Surprised the doctor suggested Dut. Isn't Dut way more powerful in both effects and potential issues? If fin was already working, not sure why Dut was necessary. Is it a requirement of the doctor for you to take Dut? I know it was either him or Couto that required fin, but never heard about requiring Dut.
On a tangent I suspect why the results of Freitas are so good is a combination of good workmanship AND the fin, to prevent any shock loss and further thinning.