I also have a Taylor lithium scale and it rarely fluctuates like that; this morning I was in disbelief at the figure (lower than I expected) and stepped off and back on several times. I even moved it a foot to the right and did it again. Then I picked up a 10lb weight and it weighed me as exactly 10lbs heavier. Stepped off, put the weight down, stepped back on, and it read 233.2. I'm willing to believe it after all that.
The thing is, it may be "off" from my doctor's scale...but who cares? It's the scale I started this journey with and I don't care if it weighs me 5-10lbs over or under. What matters is the number on that scale is moving downwards on a consistent basis...and I'm also getting smaller because I'm wearing smaller clothing than before. Those are two big DING DING DING clues that I must be doing something right.