I used to take iron supplements because I was worried about not getting enough iron. I had routine blood work and the doctor said my iron was too high and to stop the supplements. This also happened to my sister and seems to be a fairly common issue.
https://ods.od.nih.gov/factsheets/Iron%20-HealthProfessional/#h21
More info here about high iron levels.
I could be wrong but I believe they can round to the nearest 5 calories.