The isovolumetric Endopeel techniques applied for vulvar embellishment 

1. increase the length of the labia majora
2. decrease the width of the labia majora
3. increase the height or projection of labia majora

so that the product length l x width w X height h is constant.

In such case, it is unuseful to add any filler or  skin booster which would increase the volume ( as the projection already exist) and which would have as collateral effect to increase the mass as the weight of the labia majora making it older than it should appear 
Also mechanically seen, increasing the weight of the labia majora would lead to expose the labia minora.