80/90 tire on 2.15 rim

I've read many tire rim chart says that 80/90 can be used on 2.15 rim. I'm asking about this because the width of tire is 80-82mm and the steel rim width is also 80mm.

Is it okay to use 80/90 tire on 2.15 steel rim? Or it's better use wider tire like 90/90 than 80/90 on 2.15 rim?