Hmmm, mine doesn't fluctuate at all either- unless I'm stepping on it at a different time of day- my weight varies by about 3-5 pounds depending on time of day. I go by my results first thing in the morning. I can step on it from any angle and still get the same result if I hop on it a second or moments later. The only time it's off is if it's been moved at all- then I have to do one test reading (which is enough off to warn me that it's been moved) and then stop on it again.

I bought mine at Target. Can't remember the brand name...