MRc7 counts only new wood, and MRc4 counts recycled content, so there is no overlap in the credits. You must choose one credit, and not double-dip. For products with FSC Mix and recycled content claims—including many MDF products and complex assemblies that include MDF—LEED Interpretation #10372 clarifies that project teams have to choose which "environmental attribute" they will use to classify the product, and it (and its dollar value) will either go into an FSC "bucket" or into a recycled-content "bucket."