Maybe try retesting it with a heavier weight, say two 16 lb dumbbells?
My digital scale is off sometimes, and I have to weigh in a couple of times to reset it, but after that it's always accurate. The batteries are new, it's just always been like that. The thing I don't like about the old style needle scales is that it's easy to throw a weigh-in by leaning differently or being off-center. I always weigh less when I weigh in on my mom's, because I'm good at standing further up on the scale
It's frustrating to not have an accurate measure, but if I were you I'd stick with the digital scale or get a new one vs. going with the manual kind. JMO
