Correct you will need to take 70-620 in addition to 70-623 (However the order in which you take the exams is irrelevant) for the MCITP Certification. I think what Ken was trying to say was simply if you needed the additional reading material for 70-620 you would need to obtain a separate book. Good luck on the exams...
Stephen Charles Rea [MCT] askthemct.com