IMO, you would be better served to focus on reducing your SHBG a bit. This will effect your "free & bio available" test, which is essentially the FAI that you are referring to. The androgen index is your Total Test Serum / SHBG = FAI. Getting your SHBG into the mid 20's to low 30's will open up more free test.
Many people with higher SHBG can tend to be Vitamin D deficient, and E2 can have an impact. I can only refer to the E2 sensitive assay platform to gauge where a person sits. I have no idea where that assay you submitted fits in?
Anywho, again, Vitamin D can help (have yours tested), along with Netlle Root, Tongkat Ali, and/or some various anabolic compounds can work, BUT you really need to review it with a qualified physician.
To conclude for now, NO, I don't agree with implementing any testosterone enanth or cyp, or any exogenous compound. Your LH is decent, and your endogenous total serum production is excellent. If you could improve the free test % by a 1/2 a point or better, you would be miles ahead.
If you take the testosterone enanthate, your natural test (which is in good shape) is going to shutdown. When you are through with that bottle, your natural test won't be in the 700's anymore. After about 2 to 3 weeks, you will see it bottomed out. Your LH will also be low. You will then either need to look at a PCT, or you will need to continue taking testosterone the rest of your life. You don't need to mess with a good thing.
Focus on your free test & SHBG for that area, and focus on the thyroid and the other areas I mentioned for the energy /lethargic subject. Deal? TRT means replacement of testosterone .. You have testosterone, it doesn't need replaced ...
