It is better to take each test individually and not ride two boats at the same time.JEE preparation needs-focused approach and steady hard work. It is best not to upset your routine for another test. Besides, it largely depends upon where you are seeking admission. If you are aiming for IITs and NITs, it is best to ignore SAT and concentrate totally on JEE.If you are looking to study abroad, then concentrate mainly on your SAT and try to do well on SAT subject tests.