IR was designed to be a separately scored section of the GMAT, just like the AWA. What is changing with the IR is how the score is used to evaluate you. When IR was brand new, schools didn't know how to treat it, so it really had no impact on your admission and your results didn't matter. Now, it does have an impact on your admission, but you really just need to stay at or above the median score. If you are going into a field like investment banking or consulting, however, you will want to maximize your score because some firms have indicated that they may use the IR for screening applicants.
KW