I don't really follow these hair type structures because our hair is so complicated and can fall into several categories. The type of hair a person has is based on the texture and curl pattern; for instance people with Type 2 hair are considered to have wavy hair, Type 3 is more curly or slightly kinky and Type 4 hair is more kinky and tightly coiled hair. If you have 4a or 4a/4b combo it means that the hair is very tightly coiled and more prone to shrinkage from humidity and water. The z pattern just means the hair is not coiled in a curl pattern but more like a zigzag pattern sort of on angles more than in a wave. There is more likelihood of damage to the hair follicles due to heat and manipulation with Type 4 hair. More care and maintenance is required for this hair type.