Icon IC 743 piston weight incorrect
I can't see ICON being off on the weight. I probably sell 30 set of ICON piston a year and I've never had any issue with weight off that much. I am going to say your scale is off.
Order yourself a 500 gram calibration weight from Amazon for $11.99
Bonvoisin 500g Calibration Weight for Digital Scale, Class M1, Carbon Steel, Chrome Finish (500g)
I purchased one when a friend told me my scale was off and I told him I know your's is off. I checked mine and I was dead on 500 grams. When we checked his it was off 55 grams.
Using a claibration weight is the only true way to know if your scale is reading correctly. I am going to say it's off.
Tom