I had the exact same problem at my local dealer. They claim that the 2.5 liter engines are difficult to fill to the correct level and that adding the spec 4.8 qts results in different dip stick readings time and time again. I have never changed the oil in a Subaru (just got this one) so I don't know if they're full of it or there is a problem with the accuracy of the 2.5 liter engine's dipstick.
They drained and refilled it to proper level so I was satisfied. I did watch them do the work the second time and they had to drain a little out to get it right on the stick. So it did seem more difficult than it should have been.