BSA of 0.3904 is this in the range to qualify for breast reduction
It is best to address all insurance questions with your insurance company. Keep in mind that even if it may be deemed as " medically necessary", it is not always a covered expense.
There are multiple reasons that your surgery may be deemed medically necessary and BSA is only one tool that is used by a few of the insurance companies. They best way to find out if your insurance will cover this procedure is to see a Board Certified Plastic Surgeon and have your specific information submitted to your insurance. Alternatively, you may contact a physician or your insurance company and give them more detail and they should able to give you a better answer to your question.