Sorry I misread the 165 dosage. What symptoms, if any do you have? Did you take your morning dose of NP Thyroid before the blood draw for thyroid tests?
Lab test results fluctuate. That amount of difference means nothing. I would be more concerned that you are only taking 65 mg of NP Thyroid. That amount is unlikely to have any significant effect on your hypothyroid symptoms.
What was the reference range shown on the lab report for the Free T3 result? Also, what was your Free T4 level, and reference range? Did you take your thyroid med in the morning before the blood draw for those tests? Vitamin D, B12 and ferritin are also very important to a hypothyroid patient. If tested for those, please post results.
Even more important than lab test results, what symptoms, if any, do you have?