Most of our members are US bound and do not use sustanon, with that said it will be hard to draw a comparison to the esters and determine what your levels may be. It would be pure guesswork.
It takes 6 weeks for levels to stabilize, 4 weeks is too early as levels aren’t stable yet. Enanthate dropped my levels considerably compared to cypionate, I was bloated badly on enanthate which is uncommon. The bloated did subside after 6 weeks.
Most guys see no difference, but some prefer one over the other which may be due to the carrier oils used. Usually, if there is a preference it is for enanthate. At one time it was more difficult to get and I think some equate that to “better”.
I can almost guarantee a change in your numbers. And how you feel. I am not a fan of split dosing with Sustanon at all, it defeats the purpose of using it and as far as I am concerned gives you less bang for your buck. Your T level should climb on the enanthate, not a lot but it should be higher. You will also likely raise your E2. I assume that you are using the AI because you are aromatizing. I aromatize less on Sustanon but also have a lower total test level. You will find the dosing easier to dial in on E.