Weird how my OWNERS MANUAL says oil capacity= 4.2 quarts. Or as stated earlier 4.4 with a filter. I also check my dipstick after the oil change, and at every gas fill up. Something the OP didn't do. But thank you for being so concerned that I am not filling the motor I built, with the correct amount of oil.
Note: I do not say putting 4.8 quarts in is a bad thing, many Subaru shops will put that in as the MAX fill capacity. This is key, MAX CAPACITY.
It still boils down to him putting anywhere from .5-1 full quart OVER what is called for. With the design of our motors, this is not a good thing. But please, come educate me.