ok... first and foremost, some things need to be taken into consideration with how the half life and compounding of enanthate affects the serum levels and the gonadatropins (LH & FSH). there is a lot of conflicting information out there regarding half lives of these compounds. for the sake of argument, lets go with a range of 8-10 days. as the half life of each dose is reached, the amount of that dose still present is at half strength. example, 8-10 days after a 250mg shot, there is approximately 125mg worth remaining.

i'm not the one to get into how these mg translate into ng/dl in the blood. the point, however, is that the consistent doses take time to compound in the blood before they reach a peak and the level is able to be maintained. with enanthate, this is usually around 5-7 weeks.

outside of that, it is not the presence of exogenous hormones that shuts you down, necessarily. it is the excessive amounts that bring levels beyond what the body perceives as "normal" that sends the negative feedback signals of "there is too much...". it is this negative feedback that in turn shuts down the positive feedback loop, which affects the gonadatropins, etc.

until test doses have compounded and reached a point beyond what the body perceives as normal, negative feedback may not occur. 3.5 weeks is entirely too soon to gauge any of this. need to wait until about week 7 or 8, brother...

edit

i am really surprised to see your e2 levels in the normal range with 25mg ED of aromasin while on such a low dose of test alongside the DHT

I'm going to have to say that either drop the HCG, and run another lab test in 2 weeks OR your gear is bunk. Those results are impossible unless what you say you are on is not true. 25mg's of Aromasin should be killing your estrogen, and 600mg's of test a week is enough to be in the t>1500 ng/dl range.. not under 300....... Something is up.