Yes.. Your right!! You got me on this one.
It says that you need to change the lens.
However after years of working with these lights I wouldn't worry about it much. These lenses last years!!!
Now if you have them in an enviorment with alot of smoke, cigarete smoke and daily use like a club or bar, then this lens will take a lot of abuse and replaceing it will improve your output. But if your a mobile guy doing shows on the weekends, I wouldn't be to concerned about replaceing this lens.