You can't compare road vs TT positions. They are different. Where the weight is carried on the bike is not the same. In a TT and Tri position the weight is carried more forward in relation to the bottom bracket and the pelvis and torso are rotated forward. So what would be the 12 o'clock position on a road bike would be more like the one-thirty position on a TT bike. At the top of the pedal stroke, the ankle tends to come up way higher in the TT position than on a road bike. Not true of everyone but generally it's the case.
It's widely accepted that there is a penalty for going aero - That the power output in aero position does not quite match. I've heard anywhere from a few percent to up to 20... however the aero benefit makes up for the dip in power. I say poppycock. The TT position uses more of the quad and glutes where as the road position uses more of the entire leg. If there is a drop in power then it's because your quads and glutes are not as developed. I have an INCREASE in power on my tri bike from my road bike. A decade of carrying lots of heavy military gear through the worst terrain imaginable has left me 10+ extra pounds in the thighs that I can't seem to get rid of. It makes buying jeans and bibs nearly impossible.
As far as your fit goes - If you are looking to tweak fit to that level then you should see a professional fitter, preferably one in your area that is well versed in TT/Tri positioning. I'm talking the really good ones with years of experience. As a fitter myself - without watching you on the bike and having good measurements of both you and your bike, recommendations would be nothing more than a guess. Plus, why give away what has cost thousands to learn and years of experience and practice to develop.
