Thank you for your answer Kelmych. By the way, I've seen the DXTx constraints on the DDSOpt Usage Examples page where the Vanilla textures optimization is explained as well, but it seems that there's no recommended constraints for the Vanilla Normal Maps & Vanilla Compressed textures folders generated by running the .bat. So I used the Ordinary Textures constraints for the Normal Maps (not the exterior ones) and Exterior Textures constraints for the Compressed Textures. Is it the right way to proceed?