Merrit
I have a copy of the Continental Motors A&C series & O200 Operators Manual (Form X30012) It states that the quote approx maximum desirable Oil Consumption : 0.6 Quarts per hour unquote(chart on page 4). Based on that it would appear that at 1Lt per hour your engine is exceeding the maximum consumption Continental specifies in their official document. I highly recommend your group acquire this publicatio as it has complete power curves and much more engine information than the Cessna POH
My experience has been that any of your typical small 4/6cylinder engines that used more than about a litre per 3 hours has had major problems. There is no way I would personally fly an airplane where the engine used this much oil.