The fit of the resulting clothing will be dependant on the quality of the original. Here is an outline and silhouette of how well the P5 cat suit fits the P5 woman. Basically ... terrible. When converted to the P4 woman the results are as you have found out, unsatisfactory.

A better test is to convert the P4 cat suit to the P5 female. The suit fits the P4 female and as a consequence fits the P5 female when converted.