Why are they "so expensive", Mostly over $25... I know, I know, that is not a lot of money but the are just a piece of metal, nothing else.... Anyway, been thinking on getting one. I use the ones on my rcbs to check my beam scale that I just got back from Lyman and I have to say the result was not what I was expecting. However, my rcbs tends to be accurate on the 20 g test weight but not so much with the 30g so I want to check across the scale. Any recommendations/review for a set will be appreciated and taken in consideration. I think I just need one of those expensive scales....