Enhancement Scrolls

If I were to use 2 enhancement scrolls and then 3 advanced enhancement scrolls on the same item, would the success rates be 80%>70%>100%>90%>80%? Or would it be 80%>70%>80%>70%>60%? Basically my question is do the regular scrolls and advanced scrolls have their own success rates, or if each success lowers the success rates of both scrolls.