Primer Question
 

My car is in DP90 right now sprayed about 6 months ago. I was told I could not spray a filler primer over it without spraying a fresh coat of dp over it first? Is this true?

no, just sand the dp 90, if using polyester primer block dp 90 with 80 grit, if using urethane primer use 150-180 grit. use hard blocks and this will allow you to find imperfections and body work them alittle more before priming.