For what it's worth, I thought I would share this.
Last Saturday we brewed 10 gallons of Phat Tyre (Fat Tire Clone). This was an all-grain dealio.
I split the wort into two different fermentation vessels. OG was 1.053. I aerated using pure O2.
In the first vessel I pitched just the cold yeast slurry from a 2000ml starter that had been made four days ahead of time (and placed in the fridge well ahead of brewing day in order to separate the yeast slurry from the beer).
In the second vessel I pitched an entire 2000ml starter that was at high krausen.
The yeast was WYEAST #1762 BELGIAN ABBEY II.
I was curious if the two vessels would perform any differently and maybe have different FG's.
Both vessels had activity at the same time, both looked the same throughout fermentation (amount of krausen, airlock activity and swirling yeast (holy crap, it was like a mosh pit in there). Lastly, both stopped at the same time.
Today's gravity reading was 1.012 on both vessels of beer.
So, with the above data, it looks like I'm going to keep with the practice of just pitching the cold slurry. As others have said, "why put all that starter beer in the beer your trying to make if you don't have to?"
I hope I didn't waste anyone's time here, I just found the results interesting.
One thing I have found about making 10 Gallon batches is that I can experiment with different yeasts/other factors in each fermentor.