I'm sorry if I'm being stupid, I'm not exactly sure what you mean by setup.
I'm running under windows 7 64bit with an i7 cpu , 12 gigs of ram and an invidia gforce gtx 560ti video card.
For the game, I tried the 3 previously mentioned versions of forge on both my single player world and on my server. I only use 1 mod, greg's sgcraft, but I did test the issue without the mod installed, and the dropper issue was still present in the game when it was just forge only, with no mods added. I would think this mechanism should work since it works in vanilla 1.8.9.
This is a link to the tut for the auto dropper I am using;
If I'm still not giving you the information you need, please let me know, I want to be helpful, I'm just new to this stuff..