Is this right?

I know every pin machine weight is different, but I've been doing lateral raises on a pin machine for almost 2 years now. I move up in weight every couple of weeks, and felt like I was making progress until about a month ago when I felt like cable side raises would be better. Went to do cable lateral raises, after almost 2 years of doing machine lateral raises, and I can only do the first plate (5 lbs) or second plate (10 lbs) on a good day. Shouldn't I have advanced more? Stumps me that it feels like doing machine raises is way more (like 150 lbs on the machine, which is like 10 plates), but doing cable lateral raises, I can really only do the first plate. Is this common?