toolow,
DPLF is not a filling primer its a sealer , its reccomended for an excellent base between bare metal , and your primer filler ( which is for sand scratches and minor imperfections ) .
Depending on how deep the scratches are you may have to use the step down method to eleveate the deep scratches, start with 80 grit on a DA , then 150 , then 220 , depending on how smooth you want the metal ( smoother the better ) , This also helps on not having to spray so much primer filler later !
I will also say this , ALL Products shrink ( caused by evaporation of reducers and catylists/hardners ) in time , and may show those deep scratches later in the final finish , So try and get it ( the metal ) as smooth as possiable .

Spray