https://www.amazon.com/gp/aw/d/B002MQ8UH0/ref=cm_cr_arp_mb_bdcrb_top?ie=UTF8 I bought this scale in 2012..? And it's been awesome- only had to change the battery once too! It measures daily fluctuations pretty consistantly. Only time it doesn't is if you step on it 20 mins or something after its initial reading.

https://www.amazon.com/gp/aw/d/B002MQ8UH0/ref=cm_cr_arp_mb_bdcrb_top?ie=UTF8

Do you have that scale? Mine is very similar and it definitely changes slightly from one day to the next.