At 1at I had my front 2 windows tinted with 20 percent to match the rear factory tinted windows and it matched good. Then I decided to make the rear windows darker and had 15 percent put over the rear factory tint which hey said come out to be about 5 percent. No my problem is I want the front 2 windows to match again so do I have them remover the tint and re tint with 5 percent or would it be easier for them to put 20 on 20 percent would that be darker? Sorry for the long write up any info. wold be great.