In a large mixing bowl, beat together shortening, butter, sugars and vanilla, scraping bowl often, until smooth. Add eggs, beat until light and fluffy. Stir in flour mixture and rolled oats until well blended, then stir in chocolate chips. Drop batter by well-rounded teaspoonfuls on to greased (or parchment lined) baking sheets. Bake 8 to 10 minutes or until golden.