I tell all subaru customers you can only check oil cold before startup after has been sitting min of 3 hours or it will lie to you by 1 litre
Even doing that, I seem to get wildly differing readings depending on slight differences in how flat my parking spot is. Even if it does stay in the same spot, sits overnight, etc, I'll get three different readings checking three times in a row.
From now on I'll check it in the same spot after sitting. To make matters more complicated, my parking spot at home is on an incline so I'll probably just check it in my normal parking spot at work, which is flat.
I love Subies, other than some of the very poor designs (head gaskets, aluminum manual transmission snouts, and dipsticks).