Can you apply Ace hardware poly-finish Latex Acrylic over Polyurethane?

I did! I had white latex paint and added minwax chestnut brown stain to it. When I tried to mix the two to Schubert a brown color I ended up with a swirl (oil and water do not mix). I applied the mixture with a rag to an old table and the paint ended up turning a purplish color with cream and brown streaks. Almost like a milk paint look. I LOVE my "new" table!! I wish I could find more info on this technique!!