Gonzo, I have seen this topic on many boards and the short of it is, put in something less (like 4 quarts) and read the dipstick, add as necessary rechecking the dipstick.
The amount of oil you have to add depends on how much you drain. Now at first light that sounds like duh! But the thing is, it depends on the angle of the car wrt level, temperature, viscosity of oil, how long you let it drain, filter, etc. Now people have measured their drained oil precisely and have found all kinds of strange results. Maybe the manufacturers specs depend on these factors too, I don't know. But don't worry about it.
Also, when you change the filter and oil...start the car and idle for a few seconds to pump oil into the filter, through the passages etc. Then shut off the engine and recheck adding if necessary.
And if you can...post what you find.