It's different when on TRT. In these cases, if only SHBG changes then total testosterone is what changes. Free testosterone should stay pretty constant so that the testosterone clearance rate continues to match the rate of absorption.
I was basing my post on the labs I took.
Total T 690: 6 months later > 638
Free T 20.7: 6 months later > 9.6
E2 20.3: 6 months later > 12.3
DHT 74: 6 months later > 43.6
SHBG 41.1: 6 months later > 66.2
One could make a case my total T of 638 was lower than one would have expected, but it wasn't far out of line, and it also isn't that easy to predict as I take Nebido which has a very long half life, what week I test makes a very big difference. The total T of 638 was 54 days after an injection of Nebido.
DHEA also declined a lot since I stopped supplementing it, but I had never noticed DHEA causing any changes in anything other than DHEA levels.
As I mentioned, a lot of things changed, I also stopped taking HCG, along with pregnonolone and stated LEF Ultra Prostate.
These conversions of total T > E2 and DHT depend not only on the amount of T available, they depend on enzymes and other molecules in the body to work, so there are many possible reasons levels could change. In the past before this time with TRT when I was taking no hormones at all, I saw supplementing with boron increase my free T and E2 by 40% and 100% respectively without any real change in total T. FT and E2 were still low, but a lot higher than the previous test.
I saw your tread about testosterone clearance rate and SHBG, but I didn't see if that was based on theory or actual lab tests where SHBG was raised or lowered then affecting Total T.