Small changes - great improvements
You might be surprised to hear that the majority of pro cyclists never have any professional fitting done to their race bikes. Most of us probably do just what you do. But after spending a day in the lab yesterday, I can highly recommend spending the extra money on a professional fit.
The reason I suspected my position was off, is that after taking a closer look at my pedaling technique when I time-trial, I have discovered that I pedal slightly toes down. This has in effect "extended" my effective leg-length and since I had been using the generic measurements for determining seat-height, my numbers were off. This nicely illustrates why generic formulas only get you in the ball-park, you also need to take a look at individual differences.
So, this all resulted in raising the seat 1.3 centimeters. Muscles produce more power the longer they are allowed to extend, so not surprisingly my power numbers improved quite substantially.
Eager to test the actual results in the field, I ran through my 16 km TT course today and improved with almost 30 seconds. Needless to say, I'm giddy like a school-girl.