If it looks dull .....is your ratio correct for the l&p you use?
Each different brand has it's own mix ratio - of 'x' parts liquid to 'x' parts powder.
It could be a number of things.... you may be using too dry a ratio and leaving unpolymerized powder within the l&p, or it's too wet and leaving air bubbles. Or you are using too much product (pink in particular) over the white which would make the white less Sharp.
Is your finishing & buffing right, are you using the correct grits and moving up to higher grits and creating a beautiful, smooth glass like finish you can see your reflection in? If not, it could be your finishing.
Are you working in an area where you may be getting a draft, which will affect the polymerization process and even cause the monomer which is un-polymerised to evaporate quickly, leaving a powder residue that just falls off when filing?
These are some of the problems I've encountered over the years.
It could be quite a few things as you can see, so, could you explain in a bit more detail- or even better post us a picture of the enhancement to look at?