As discussed in a separate article in this blog, notice the temperature warnings for fine and chemically-treated hair? In this newer literature, the warning is at the beginning of the paragraph, right? Reminder: Chemically-treated means color treated or relaxed, etc.
This is a picture of older FHI Heat Literature. Look at the "Temperature Settings" paragraph. Notice the same warning? Notice that in this older literature, the fine and chemically-treated hair warning was in the middle of the paragraph? So the newer literature pictured above emphasizes their warning about the dangers to fine and chemically-treated hair by moving the statement to the first sentence. Were they becoming aware of the damage that was happening?
Look at item number 6. Notice that instructions say hair should glide through iron without pulling nor gripping? If you have curly hair, you are more than likely shutting the iron tight trying to get the curl out? If you are already straight and just want to control some frizz, then a lower temperature, some flat iron serum and a simple pass should do the trick. But for curly hair and fine hair, why spend over $100 for a hot tool that is not designed with the health of your hair in mind?