I have the Pro-Series 4 Vertical Smoker and have used it about 5 times. Even though it's level, I've noticed that the grease tray doesn't ever have grease in it, yet I'm emptying/scraping out grease from the bottom vent cover and water tray. I line the water tray with foil, but it's quite the clean-up after a few pork butts and wings. Just wondering if this is normal or if there are suggestions? Thanks.