I contacted the Canadian company and this was their response
Thank you for contacting Erfa Canada 2012 inc. Your physician is
correct. Since your TSH is low this indicates you are taking too much
Thyroid hormones. By reducing the dosage your TSH will increase and you
should be fine. Being on a low TSH can become problematic since taking too
much hormones for a very long time can cause osteoporosis.
Hope this helps.