My mom still uses her cast iron on her glass top. She has the same griddle pan you are talking about and it has worked fine. I remember as a kid using it. I think you need to be extremely careful not to slide the cast iron on the stove or it will scratch. Pampered Chef used to sell one in a style I believe was safe on smooth top. I am not going to say my mom hasn't scratched hers but I think that is actually my dad and I don't think it can be blamed on the pans.