Newer model fridges are a bit more tolerant than the older versions, we level our rig for comfort purposes anyway and we're pretty close to level in all directions. The more often you operate the fridge out of level, the quicker the possibility of eventual clogging and failure. Less critical traveling down the road as the mixture continues to flow due to the constant movement. Our Dometic has performed flawlessly over the last 6 years no matter the outdoor temps and we believe keeping it level has contributed to it's consistent performance.