The last time I got shorted by the stealership it wasn't even showing on the dipstick after the check oil procedure. One US quart brought it up to the bottom un-crosshatched part of the stick, maybe 1/8" showing. At that point, I added another whole US quart and it came up into the upper part of the crosshatch portion, after the idle/wait procedure. So seeing that, I'd only add half a quart if it were low and recheck. Unless it was very low on the crosshatch portion a whole quart would probably be too much.
Now, I'm wondering what oil they put in it. Probably that cheap bulk drum of semi-syn. I wouldn't trust one any more than I could throw one. hurl