That's...a pretty wide spread no? Wet or dry sump?
My Outback lists 5.1qts, it gets 5. The Equinox lists 6, it gets 6. Depending on the size of the filter can, it all evens out. The really annoying ones are the .5's. The GM 4300 for instance, lists 4.5 qts, I always dumped the full 5 qt jug.