Defective Scale?

ieatstickers

I have the Weight Watcher's Body Analysis scale and its been true since the day I bought it. But recently it's been giving me different readings every time I go on the scale. I know a low battery can affect a scale's accuracy, but its a lithium battery and my scale hasn't blinked that it's low yet. I plan on buying a battery for it soon, just so I can stop relying on my analog scale, but I was just wondering if anyone else had this problem and if replacing the battery fixed it. I'd hate to think I wasted $50 on a scale that's now defective.