I just bought a Graco sprayer to paint the interior of our new home. I sprayed primer on 2 13x13 bedrooms and the closets in each, an 8 x 7 bath, a hallway closet, and tiny hall area that connects the 3 rooms. It took about 12 gallons to do this. The first bedroom alone was almost 5 gallons. I know this can't be right, any ideas?