A well built and highly tuned Duratec should not be using 1 ltr per 1000 miles
If i had a guess i would say too many revs when the engine oil is not up to temp has worn the piston rings( this is the quickest way to wear your engine out), which is exactly what had caused of my previous high oil consumption.
After the extensive upgrade and rebuild it was not using any oil and the addition of a stack oil temp guage showed how far behind the oil temp was compared with the water temp.
Solution was to add a Laminova, now the warm up time has been cut in half.