I have never lost any oil on either of my Duratecs, one with 70k and one with 37k. Granted, you're way beyond my mileage... How often do you check the oil? I try to check all my fluid levels at least once a week. Keep a close eye on things for the next few months. It may have just been a leaky seal on the filter or drain plug. Put some fresh cardboard under the engine (big enough to sit under the filter and drain) after a drive and leave it overnight, maybe you'll catch a leak. Otherwise, refer to previous posts...
