While it's easy to assume that you will perform the best when you are near the bottom of your weight range, an "ideal" race eight is not a guarantee of having your best performance on race day. I can assure you that even if you lose fat from your butt, thighs or stomach, you won't become a better athlete on race day just because you weight less You still need fitness and good health to perform the best with your body so the idea of "weighing less" is not effective if you are just chasing a number on the scale.
Karel and I have never ever chased a "race weight." Our goal is always to arrive to a race with a body that is resilient, strong, healthy, injury-free, fueled and fit. We have no rules in our diet and we never assume that weighing less will help us be better athletes.
As an athlete, you must accept that your body will change throughout a season and year after year. Assuming that you must weigh the same (or less) to experience continual improvements in your sport may put you at risk for health issues and constant frustration with your body. The constant chasing of a race weight may also increase the risk for disordered eating.