need advice on paints..can i reduce PPG DBU basecoat with OMNI MR 186?? :waving

Why? Sure there may be a small posibility that a PPG rep can tell you that these two products are the same. But as far as I know OMNI is a "stand alone" product and doesn't share any components with the high end PPG products. Base coat reducers often contain resins and even activators. I don't know about these PPG products but in the general sense unless you knew CHEMICALLY that they were the same I can't imagine taking the chance when the proper product is available at the your friendly neighborhood PPG jobber.