Yesterday was a good example. The SPX had a 3.7% move, although it started preopen. For the average fund that 3.7% can easily be half of their annual return, so with today's volatility there can be a huge difference how they time the flow... My guess is that overall it evens out, sometimes they time it good, sometimes they time it bad. I am still curious about how they credit the loss/profit over the EOD data.
If I understand what you mean I think you can change the numbers in the example I gave you earlier and figure this out.